This is somewhat more specific to your question about murder then some of the other (excellent) answer, but I feel the need to point out this rather simple solution to the "murder" question.

Ressurection and equivalent spells all say:

If its soul is free and willing, the target returns to life with all its hit points.

This might depend somewhat on who has been killed, but most people that have just gone through a traumatic death and have went on to whatever appropriate afterlife probably don't have a lot of reasons to come back.

Your rich guy can be all smug and "I'll just fix them" and spend a bunch of money and then the spell just fails because their victim is pretty content being in the afterlife and doesn't really want to go through more life (and trauma and death), especially not if they're aware they are being raised by their murderer.

The only people that will gladly come back are the ones who have some kind of horribly evil plan or went on too a horrible afterlife. In which case, story opportunties aplenty because they probably just ressurrected someone they'd rather have stayed dead and they'll probably come back with a vengeance. (And modify memory might make them forget they were murdered, but it won't make them forget their evil plans)

I realise that I'm very late in replying to this question, but I think there's a key assumption in there (which was accepted by all the answerers so far) that isn't sound.

I don't believe that Modify Memory would suffice to erase the trauma.

Let's look at some quotes from the original post.

I pointed out that the trauma would still be criminal, and he responded that he can just cast Modify Memory, so the person will have no memory of the incident (which could be beneficial to both parties; the option to not even remember a traumatic experience seems pretty tempting to me).

If the person is restored to life and no one remembers the murder, it seems like no crime has been committed.

Assault (and even some more heinous crimes I won't mention) can be "fixed" with healing/modify memory. Rejuvenate / reincarnate will even restore body parts.

PTSD causes physical changes to the structure of the brain. For instance, the website of the British NHS states

"In people with PTSD, parts of the brain involved in emotional processing appear different in brain scans. ... the hippocampus appears smaller in size. ... The malfunctioning hippocampus may prevent flashbacks and nightmares being properly processed, so the anxiety they generate doesn't reduce over time."

It can also have other physical/chemical effects. From the same source:

"Studies have shown that people with PTSD have abnormal levels of stress hormones. ... People with PTSD have been found to continue to produce high amounts of fight or flight hormones even when there's no danger."

(The effects of PTSD on brain structure, epigenetics etc. are complicated, and I don't claim to understand all of it. I won't post an exhaustive list here.)

Now, Modify Memory might eliminate some of the PTSD symptoms. If all memory of the event is removed, the victim may no longer have specific triggers. However, according to the NIH, some symptoms are constant, not triggered by reminders of the event. Such symptoms include angry outbursts, and difficulty sleeping.

So we have evidence that traumatic effects could persist after the resurrection/healing and the mind tamper. The victim's loved ones/friends/associates will notice these, and may recognise them as PTSD symptoms following a traumatic event. If they report this to the authorities, investigation may reveal that a crime was committed. The victim may not remember the crime, but they will be realising that something isn't right.

And then there's another complication. Modify Memory might not work properly on these memories.

I'm not sure how reliable a source WebMD is, but:

With PTSD, your brain doesn't process the trauma the right way. It doesn't file the memory of the event as being in the past. The result: You feel stressed and frightened even when you know you're safe.

If the memories are garbled, stored wrongly in the brain, perhaps Modify Memory might not work on them as usual? This would be up to the GM to decide, I think. But if fragments of the memories survive, and things that bring the memory fragments to the surface trigger the victim, they (and the people they talk to) might be able to piece together a picture of what happened by looking at what the trigger factors are.

The way in which these memories are stored/accessed wrongly is discussed in this peer-reviewed article, including the following quote:

the notion that what makes memories traumatic is a failure of the central nervous system to synthesize the sensations related to the traumatic memory into an integrated semantic memory

And this one:

it has been understood that traumatic experiences can leave indelible emotional memories

Indelible may well translate to "can't be modified by magic in the same way as other memories."

Or (and this one I'm really not sure about)... if the victim is suffering the effects of trauma, and if the mechanisms for "triggers" are there but the victim's triggers have been erased... could things the victim sees and experiences in the time period after Modify Memory turn into a new set of triggers? I'm not a doctor, so I would welcome replies in comments from experts here.

Looking at other PTSD symptoms the victim may suffer, "People with PTSD have decreased brain activity in the dorsal and rostral anterior cingulate cortices and the ventromedial prefrontal cortex, areas linked to the experience and regulation of emotion."

Avoiding the mechanics/neuroscience for a second, let's also note that:

Individuals diagnosed with PTSD experience significant functional impairment, including increased risk for unemployment, disrupted relationships, and diminished physical health

(source)

The players could well be held liable for damages as a result of this.

English legal historian here ... echoing what some others have said. Not that you need to mirror the English common law system, but if you did -- The system takes account of several aspects of a crime:

1. Harm to victim. This might be pecuniary loss, or pain and suffering. And it might be sub-divided into ephemeral (short-lived) and pervasive (long-lasting) harm. This might be wholly absent in certain circumstances (or even categorically for certain types of offenses). This matters not. To be deemed criminal, an act need not involve harm to a victim (or, indeed, any "victim" per se). Note also that the term "victim" can be expansive--the "victim" of a murder is surely the deceased, but it might also be said to include surviving loved ones who endure the loss.

2. Harm to society. Crime disrupts social order, and lawlessness begets lawlessness. Therefore, any crime visits some quantum of harm on society.

3. Moral blame. For certain crimes, punishment is imposed (at least in part) for the moral blameworthiness of the act, regardless of its consequences. From our vantage point in history, moral judgment by a legal system might seem quaint, but in the past legal systems were seen as being reflections of the moral laws of God (or Nature), and in fact concepts of "natural law" persist in our legal system to this day. An example is a class of offenses deemed "crimes of moral turpitude"--acts that (ostensibly) are criminal because they are naturally/inherently evil or otherwise morally wrong. So, littering might be an offense against social order but not a crime of moral turpitude. Whereas battery or, more controversially, various sex crimes are deemed crimes of moral turpitude. The moral blameworthiness affects the degree of punishment. So, a murder committed in the heat of passion may receive a lower sentence than one committed in "cold blood."

To apply the above to your circumstance, the magic in question can mitigate and even wholly alleviate the first aspect, harm to victim. But it would not seem to address harm to society/social order, or--crucially--moral blameworthiness. Which is to say that under an English common law system, the act would still be subject to suitable punishment.

Of note is that the consequences of suffering a conviction for a crime of moral turpitude extend beyond the immediate punishment imposed in the criminal legal system (e.g., a monetary fine, imprisonment, a period of hard labor or involuntary servitude, physical torture such as whipping, or marking the body with a brand). The social stain lingers. For instance, innkeepers may not let a room to such a former convict, and others may not employ them. Banishment is possible. Indeed, this is in fact a prominent aspect of contemporary immigration law in the United States, where a conviction for a crime "of moral turpitude" may be a deportable offense.

The gods are not amused.

Once mortals are powerful enough they start to draw the attention of the gods. Powerful enough to reverse death would qualify.

Keep in mind the people you harm or kill worship gods and gods have power in DnD. If they are specifically devout or important the gods themselves may turn against you. Perhaps a god of justice puts a bounty on your head, or informs their priests of your crime or drops a geas on you as repentance. Perhaps the god of trickery decides the players have performed a great act of trickery and now deserve his (incredibly annoying) attention. Sometimes just the attention of a god is problem enough. Or perhaps the god of death is not happy with them using Resurrection so casually and decides to inconvenience them with special attention or simply by informing others of what they have done.

Also who cast Resurrection? If it is a cleric their god may be unhappy with them using it in an attempt to erase a crime, and may punish the cleric.

Resurrection requires a willing spirit, who says they are willing? Perhaps they are more angry than anything else and the players now have to deal with a vengeful spirit.

If you need to punish the players or make them feel guilty, one solution is to create a vigilante justice/vengeance subplot.

For example, using the murder: your players murder the official, then revive him and wipe the memories of everyone who is involved. Or so they think...

Later in the story, they start finding strange omens, perhaps discovering ominous messages scrawled on the walls when they awake in the morning. Build up some dramatic tension, and then a new character emerges from the shadows. The murder victim's bastard son, or secret lover, or long-lost sister has come to seek revenge. This individual saw what happened, but escaped the players' notice. They have been stalking the players, waiting, biding their time...

To try to give it more emotional impact, and prevent the players from using the "oh, we revived him so it's all good now" argument, you can say that when the players wiped the revived official's memory, they unknowingly erased the memory of the bastard/lover/sibling. This character, yelling through tears, explains how they have lost everything through the callous actions of the players.

If the players are too high level for this vengeful character to battle them directly, try something dark to introduce a suitable threat. Some ideas:

• The character sacrifices him/herself to summon an arcane terror. (If the players defeat the terror, revive the character, and wipe his/her memory, try to make the revived character so pathetic, confused, and hopeless that the players can't help but feel guilty)
• The character reveals that they paid a terrible price for vengeance. They turned traitor to their own people, perhaps sold out the very official they loved who no longer remembers them, in order to buy their revenge. As the character fades back into the shadows, an army emerges...

If you want to really drive home the emotional impact, try to tie this in to something from earlier in the campaign. The vengeful character turns out to be some minor character they assisted or rescued earlier in the campaign. The bastard son of the official turns out to be the same boy they rescued from goblins early in the campaign. The players gave him freedom, and then took everything from him again when they unknowingly erased him from his father's memory.

If the players keep at their shenanigans, keep using the law of unintended consequences to have karma bite them in the rear.

All of these answers are great, but I'd like to propose another option.

Trap then in an endless series of appeals, counter-lawsuits, personal injury suits, evidentiary hearings and arguments over admissibility while they run up exorbitant attorney's fees. Then provide them with a way to settle that involves an admission of guilt, some form of punishment and/or restitution that the family of the victim (or the resurrected victim) feels is appropriate. This is also a situation where a good personal injury lawyer could squeeze them even after a resurrection.

No matter how rich someone is, the legal system can almost always find a way to break the bank. If you want to get a little cloak and dagger about it, you could have a concerned but anonymous third party bankroll a legal attack against them as outlined above (look at the Gawker vs. Hulk Hogan lawsuit for inspiration).

Could be fun.

Laws apply differently to rich people in real life

We don't have resurrection, but this happens in real life too. Bribing judges, getting lesser sentences because of status, getting a comfier jail cell, having a fine instead of incarceration, etc.

Why don't rich people abuse this power constantly? Well, they do. However there are different consequences for the rich:

• Public opinion. Rich people often rely on poorer people for many things. Being widely reviled and dislike can have serious consequences for even the rich. Your rich player may find that common folk hate them and refuse to deal with them, causing all kinds of problems.
• There are other people who are richer. You can pay for a resurrection spell, what can your enemies pay for? The King is richer than you. If the King wants you dead enough, you will stay dead.
• Loss of business connections. If someone is widely believed to be breaking laws that are unsavory, public opinion will turn on them, and other associates don't want to deal with them for fear of public opinion turning on them too. The once reliable fence now thinks the character is too much trouble.
• Opinions of peers. Even if you get off, your peers may not like you anymore. They shun the player and don't want to have anything to do with them. Friends dislike the character, the party has to pretend they don't know or dislike the criminal.
• Institutional limits. Being a criminal bars you from all kinds of services. A known criminal may not be allowed into certain areas or groups, regardless of their absolution. The resurrected criminal may not be allowed back into the city, into the temple, or into certain guilds.

There are huge and varying social consequences that affect criminals, even if they have evaded legal punishments or "undone" their crime.

Modern Legal Equivalent

Conspiracy to commit murder is still a crime in the US, even if the ultimate murder doesn't happen. Attempted Murder is still a crime in the US; even then the victim is ultimately unharmed. So, if anyone mortal knows it happened, there could normal legal consequences in your game world. A thief is still chargeable for theft if they return the stolen items under most countries laws.

Taking someones memory without consent is likely its own transgression. Even a traumatic experiences help shape who we are. If someone wants to forget something traumatic that happened to them, and has the spell cast on them; that is fine and dandy. If someone just removes or modifies someone else's memories without consent, especially to hide a crime, that is likely its own crime.

Modern Wealth Issue

Yes, coin can sometimes unjustly shield the guilty from the consequences of their actions. Bribes, pay offs, blackmail are things that happen in the real world. One potential option is to use this as consequences. If someone powerful knows of the deed, and needs the party to do something, they could blackmail the party. That third party can be human, or something much more sinister.

I know what you did. You have money, and talent. It would be a shame for that talent to go to waste if you were ever arrested. So, what if we ... make a deal. You do X, Y and Z for me, and we pretend it all never happened.

Trial is the not Only Option

If the accuser can't accuse them, and no one knows it happened, there won't be a mortal trial. But you have a game in which gods and other super powerful being grant magic spells to do any sort of tasks for them. Bahamut, for instance, is a god of justice who could send clerics or paladins or metallic dragon followers after the party for their transgressions.

Or maybe, the victim is resurrected by a different powerful source (as a warlock or as a revenant), before the party can revive them. Maybe they made a deal, and now the party is pursued by the victim seeking revenge.

A character can only be brought back by resurrection spells willingly. Maybe the character likes the afterlife they land in, or likes being a ghost who can haunt the party.

What is the court intended to accomplish?

Step away from your initial problem for a moment. What is your judicial system supposed to accomplish? Why do you have courts at all?

Some (real world) ideas that may be useful:

• Retribution: Criminals deserve to be punished. Punishment is not intended to "fix" problems, it is intended to punish people for wrong-doing.
• Restoration: Criminals should be confronted with their actions and repair the harm done. The idea of punishment isn't as prevalent here, rather the focus is on fixing the effects of a crime (which may be more than material!).
• Rehabilitation: Criminals require some education, training, or support in order to stop committing crime. While there are likely some kind of punishments or penalties in place, the focus is really on making sure that the criminal doesn't commit future crimes by providing them counseling, vocational training, and other supports.

Once you answer why you have a legal system at all, the answer will become a bit easier.

Applying that to your game

Now that you know in-game why the legal system exists you can make it work for you.

You've said your players have access to incredible wealth. This means they could trivially fix many material problems. However, a retributive justice system wold care very little - they are going to be punished for their crime even if they fix it. Additionally, the misuse of their wealth for criminal actions may make the punishment more serious.

A restorative approach to justice plays well to the PC's strengths: they can pay their way out of many problems. But there are many intangible things which might be at stake, i.e. threats to individual memories, culture and legacy, a sense of safety and security. Wealth will help, but not fix, these problems.

A rehabilitative justice system will focus on the characters personal growth and teaching them not to commit future crimes. Wealth will not help. If they are found guilty, the players can't buy their way out. They will have to undergo some kind of training or process to reduce their risk of not committing future crimes. You probably don't want to RP out therapy sessions (or maybe you do, you avant-garde gm), but some terms may be more interesting to adventures. Consider the role of magical means to detect these crimes (like a court-appointed scryer, or a constant detect thoughts-type ability).

Second-Order Effects

Your justice system will result in other effects across society. These will help answer some other questions.

For example, you also raised the question of how Wish spells and other magical things would influence crime and justice. However, the existence of your legal system will influence what is available and how available it is.

For example, in a rehabilitative justice system, people will to accept cash for an illicit Wish spell are probably few and far between. Once a spell-caster with criminal leanings is caught early in their career, they are rehabilitated. So although the rehabilitative system may seem soft in some senses, it also limits the help your PCs are going to get. There may simply be no one who can be bought.

You should also expect law to extend to the magical world. Sure, Wish can solve a lot of your problems, but not if spell casters capable of casting it are bonded, licensed, or monitored some other way. The law is probably monitoring those people - including your PCs.

Parting Thoughts: This is an invitation to you as a GM

As a parting thought, consider this challenge an invitation think about the fictional legal and political world that your characters inhabit. What do the people of your world expect from their legal system? Is it effective? How does it maintain fairness in the face of powerful magic? How does it make sure that judgments are implemented correctly? You'll end up with a more interesting game world and more satisfying game experience.

And even if your players just go back to slaying dragons, you'll know how to handle the inevitable problems about exporting the body parts of endangered species.

Restitution does not mean "not guilty"

• If I embezzle money, use it to win the lottery, and then pay back all that I took, I'm still an embezzler.
• If I steal a car, drive to Las Vegas and back, then return it with a full tank of gas, I'm still a thief.
• If I try to kill someone, but they manage to live, I'm still an attempted murderer.

Same rules apply, regardless of magic. Just because you put things back to right, or made it look like it never happened -- you still did it! And you were caught!

So you killed someone and brought them back to life. They were still dead and suffered any consequences of that (what happened to their soul before returning).

Even if you Modify Memory of the victim, what about:

• Relatives that were told about the death and grieved?
• The person that discovered the body and the nightmares that haunt them?
• If there was a trial, all the people involved with your grizzly act?

The character could spend months or even years trying to make it all go away. And even then, what about the people indirectly affected? Rumors spread very quick. Plus think of how this will affect the noble family name?

There are always repercussions to actions, no matter how hard you try to cover them up.

You can have the legal system treat the crime as punishable whether or not they "undo" its effects - in fact, I feel that's more realistic; I'd expect most civilisations to frown on people being assaulted and having their memories forcibly changed, even if the victim is no longer able to object.

As a GM, I would have this start to affect other people's opinions of the PCs. Even if the victim doesn't remember what happened, any other witnesses might - you've mentioned that they were caught, which means other people can have an opinion. Mistrust and fear is a completely reasonable reaction to this kind of behaviour. If you want to really bring it home, you can directly refer to it - have someone react badly to them and explicitly refer to the murder, resurrection and memory modification thing as what they're afraid of.

Finally, it bears mentioning that this is partly an OOC expectation-setting question - you mentioned that the player raised this out of character, so I think it's worth being clear OOC that merely putting things back to how they were before the PCs crimes won't completely negate any social consequences, so the players don't feel cheated when it comes up.

Resurrection doesn't absolve anyone of a murder already committed

I may be getting a little close to real world religion here, but absolution comes from without, from the agency of another, not from one's self.

absolution noun: formal release from guilt, obligation, or punishment.

While the spell undoes the effects of the crime, the act of harming was not undone. The situation you describe could be handled similarly to 'tort' law (in the Enlightenment / Western sense) rather than criminal law: one goes to court with the objective being that the crime victim be "made whole."

Beyond that, there are the issues of things like triple damages, right? evil grin

As you point out, the trauma of having been killed, even if the victim is subsequently resurrected, is not undone. Putting on our Feudal / Medieval / Renaissance era hat¹, since that is what a lot of games like this try to assume as a setting, you still have the problem of "you did me wrong, I want to be made whole." You could apply something like a 'weregild' or even have the killer be declared 'outlaw' by the government as a consequence of the murder.

1. Weregild

   (Old English: “man payment”): in ancient Germanic law, the amount of compensation paid by a person committing an offense to the injured party or, in case of death, to his family.

2. To be declared outlaw ...

   ... was to suffer a form of civil or social death. The outlaw was debarred from all civilized society. No one was allowed to give him food, shelter, or any other sort of support—to do so was to commit the crime of aiding and abetting, and to be in danger of the ban oneself.

3. Consequences: as Grandma said, you shouldn't have done that in the first place!

   'Tis well that the court should acquit thee
   'Twere best hadst thou never been tried
   (From an old poem called "The Laws of the Navy")

Short answer? Treat it as a civil case, not a criminal case.

Cleric and wizard at level 13. They have access to 7th level regenerate. The cleric chose the noble backstory, and has a good bit of gold to burn.

Well, if he has money to burn, hit 'em with triple damages. The cost of the spell, times three, as a fine. Or, think through this like a "wrongful death" case and levy a huge judgment / fine that hits the cleric for about how much gold they have ... OK, they have to go and adventure some more, as they are now broke.

Money can't buy back a soiled reputation, nor buy absolution

Consequences? This (cleric) noble's reputation is tarnished. The party associating with that cleric is also held in a dim view per the old "you hang around with that crook?" vein of public shaming or rep harming. I suggest that you take a look in the DMG on the "Honor" optional ability score for ideas on how applying reputation or honor in game might be useful here.

You'll never work in this town again! (Exile)

They can still be exiled for having committed the murder, unless the weregild, or other suitable damages, are paid and they do a whole big public atonement deal. There is a nice Game of Thrones example: Cersei Lannister's walk of shame was such a public atonement, but did that really restore her rep? Maybe in the eyes of some.

An old school example

While not a 5e example, we had a party of 7-9th level characters who got into massive trouble with The King (AD&D 1e). Why? We killed the heir (we didn't know he was the heir; he was running a side scam with a Thieves Guild). We were able to afford a raise dead spell, and we paid for it, but the King was not amused with our assault on his bloodline.

We were declared outlaws. As a result, we fled the kingdom and undertook adventures elsewhere. And, we did have to contend with bounty hunters for the rest of that campaign.

---

¹ _{@pboss3010 raises the valid point that there's no reason to apply "modern" legal thinking. Your typical medieval fantasy has no reason to have a Bill of Rights. Double jeopardy, cruel and unusual punishment, no speedy trial, all of these are in play}