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Alfred is on trial. He stands accused of murdering Frank. He was caught red handed with a knife that tested positive for Frank's blood. He was also seen dumping Frank's body into the river by Bob, Frank's brother, and Mike, Alfred's best friend.

It seems like an open and shut case - except for one thing.

Alfred lives in a world of MAGIC.

Alfred's lawyer tells him to play the 'Illusion Defense'.

The Illusion Defense plays thus - since Illusion Magic is rare but possible, any event can be called into question.

Alfred claims that when he picked up the knife, in his eyes he saw a bottle of water. He also claims Bob and/or Mike were tricked by an illusion as well, and that Frank's body could be anywhere by now. This is complicated by the fact Police Teams haven't found the body yet.

Assuming 1) In this world you are innocent until proven guilty and 2) that CCTV doesn't exist or can just as easily be tricked by illusion magic, how does the legal system protect against 'The Illusion Defense', or how does this Magic World determine the truth in criminal cases?

Edit - Regarding Magic

In this world Magic is used primarily amongst the Military and Elites. Basic fireball-esk magic is common enough, to the point where entire military divisions consist of entirely magic users. Less than 1 in 100,000 would ever manifest anything significant on the level of Illusions.

Elites also have access to magic artifacts which can focus an individuals Will and produce various effects. At lower levels it merely improves an individual's health. At higher levels, an individual can fly, lift buildings or in some cases conjure illusions.

There is of course also the omnipresent specter of Forbidden Magic which is where the greatest use of Illusion is likely to be. In short, the most common use of Illusion Magic will be by those committing or trying to cover committed crimes. The rest of the time there isn't really a need for it outside of stage productions.

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Welcome to the site, Volastem. Could you provide some detail on how magic works in your world? Magic systems vary greatly from world to world and author to author, so we ask questioners to detail their brand of magic to let answers be more focused. – Frostfyre Jan 4 at 18:43
Check Wizard Barristers. – Ahriman Jan 4 at 19:13
Thank you. I've updated my post with an edit. – Volastern Jan 4 at 19:14
I was just wondering, how would he get away with saying he thought the knife was a bottle of water? I mean, the way a water bottle looks and a knife feels are two VERY different things. – XandarTheZenon Jan 5 at 0:03
Play the "No body, no murder" card. If there's no body, they can't be sure the victim is actually dead. – Mast Jan 5 at 14:31
up vote 36 down vote accepted

"… how does this Magic World determine the truth in criminal cases?"

A forensic wizard casts a lie detection spell on Alfred. In normal circumstances Alfred could exercise his legal right to refuse to testify under the influence of magic, but obviously if he's using the Illusion Defence he must waive this right.

Alternatively the forensic wizard could perform an object-reading spell on the knife.

Naturally, the courtroom and police headquarters are well warded against crooked magic users attempting to pervert the course of justice.

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Hmmm. Clearly there does need to be magic within the Judicial System. Given that it is mostly the Elites who have the Magical Power it wouldn't be surprising if there was a degree of status involved with being part of Magical Prosecution. I suppose the issue then is how to prevent entirely families subverting the entire legal system for their own gains. Hmm... – Volastern Jan 4 at 19:16
"how to prevent entirely families subverting the entire legal system for their own gains" - one could argue that this has already happened in our existing legal system .... – brhans Jan 4 at 22:11
@Volastern If you can figure out how to prevent subverting the legal (and financial) systems of families who don't even have magic, please let everyone know! That would be a Nobel-prize worthy sort of finding :) – BrianDHall Jan 5 at 16:52
"...could exercise his legal right to refuse to testify...' This right is a modern (i.e., mid-Enlightenment) development. There's no reason to assume it exists in the medieval-themed cultures that most Magic narratives are set in. – RBarryYoung Jan 6 at 16:10
The reference to "a knife that tested positive for Frank's blood" in the original question suggests the setting has a fairly modern level of technology. The use of familiar Anglo-American names like Frank and Alfred suggests it is a parallel world to ours. – Lostinfrance Jan 6 at 16:34

The Order of The Stick touched on this briefly in the opposite sense, that "Detect Truth" can be just as faked as any illusion. So the court can't just "Detect Truth" on our Alfred who is using the illusion defense - because it can be just another illusion. Instead, the witnesses, blood type, and evidence were considered to be more accurate than anything else. I really appreciated this model - as it is, traditional magical court systems (See edit below) seem to rely more on tests than anything else. (She floats, she's a witch!, etc...).

Edit - For example, the court used by Azure City relies solely on a being of pure Law and Good to administer justice - such a system isn't much of a trial. The Bloodstone system in the comic is corrupt and just sends everyone to a prison. Both of these examples make fun of purely lawful good or lawful evil systems, while the Cliffport system makes the most sense.

The best method seems to be to put the testing laboratory and the courthouse in anti-magic zones. While eye-witnesses will tell what they witnessed (as an illusion or not), and a liar will keep on lying, the anti-magic zone will keep evidence as, well - evidence, and not an illusion, and the trial proceeds as normal.

In regard to disproof of an illusion defense, the prosecution should begin with motive and means (who could cast an illusion, wants to frame Alfred and wants Frank dead?) and proceed from there, same as in a case of "I was framed!". It just turns out that, well, illusions make it really easy to be framed, so you've got easier means, but nothing else.

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Welcome to the site Mark – James Jan 4 at 21:41
Thank you. I really like this answer. Rigorous analysis of evidence combined with the burden falling on the prosecution to determine the reasons and motive for casting an illusion. It would also be in the benefit to the Defense to explore this line of inquiry too because any evidence uncovered could form a tighter alibi. As you say, ultimately it becomes just an extension of 'I was framed' with a more sophisticated way of going about framing. – Volastern Jan 4 at 22:04
The counter to that is to use illusion magic to dupe the entire courtroom full of people to think they're in the anti-magic zone, but actually they're in a warehouse somewhere seeing an illusion of the zone. Works especially well if teleportation magic is a thing that exists. Ultimately it becomes an arms race between the criminals' illusionary prowess and the court wizards' abilities to detect such trickery. – Darrel Hoffman Jan 5 at 16:36
Yes, active maintenance of the anti magic zone would be a very prestigious position, for only the most effective and trust worthy casters. This would be a very highlighted point in the story. – Mark Jan 5 at 17:09

It heavily depends on how magic works in your world, in particular:

  1. If magic is very rare, then this kind of defence wouldn't much better than a line of defence in our world amounting to "everybody hallucinated". If magic isn't that rare this line will be taken more seriously, but also...

  2. ...if magic is a common thing then forensic science/magic would probably evolve in trying to gather proofs of type, intensity, forms etc. of a particular magic involved. If a court is supposed to maintain today's level, there necessarily will be forensic magic experts trying to gather evidence which might or might not support the described line of defence. If there will be sufficient evidence in support or even if a magic expertise will claim consistency of Alfred's description with how such magic is known to work, Alfred might have reasonable chances to defend himself against the charges.

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Thank you for your reply, I've made an update regarding the nature of magic. As you say, its a case of finding evidence which is hard given that there is unlikely to be anything obvious at the crime scene (if it is actually the crime scene...) – Volastern Jan 4 at 19:21

It would be interesting to know if magic use leaves any residue. Stuff like runes, sigils, wards, fairy dust, whatever.
Things that could be found by investigators.

Alternately, like in our world, the police could look for other suspects while still holding Alfred.
Who else has a motive for killing Frank? If Alfred wasn't down by the river dumping the body, then where was he? Where is the body? A good investigator is going to look at all the possibilities, and if the body isn't in the river, then maybe they can look for it elsewhere.

The killer could have actually dumped the body in the river, and used illusions to make himself look like Alfred. And Frank might not have an alibi. But forensics would still be really useful even in a magic world.

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Indeed, holding objects will always be an important part of the case. Its just a case of any eye witness accounts can be falsified. Even if Alfred is seen in 2 places at once, which was the illusion - dumping the body or out shopping? – Volastern Jan 4 at 19:19
@Volastern Is Alfred a magic user powerful enough to produce illusions? If not, and if he used illusion to cover his dumping the body then that means he has an accomplice. If he is that powerful, why wouldn't he use illusion to stop anyone from seeing him dumping the body? It also implies a lot of forethought, and so being caught with the murder weapon (and not dumping it with the body at the very least) is pretty dumb. If I was a cop, and someone was caught with the weapon after dumping the body, I'd be suspicious. – AndyD273 Jan 4 at 19:44
Also, shopping would require interacting with a lot more people, picking up stuff, etc. Unless the illusion can simulate all that (which sounds complicated) It seems less likely that he would create an illusion to do that. Maybe have an illusion sit in a theater box or something where people can see it but not ask it questions... maybe. – AndyD273 Jan 4 at 19:46
Casting an illusion to change one's appearance is possible and yes, an accomplice could be involved. Mistakes could have been made that resulted being caught in the act. In the end, there's usually something bigger at play, however this is just a single case. – Volastern Jan 4 at 20:17

The first strategy would be likely the same also applied in the real world for things you can't directly verify: Question the suspect in order to find contradictions in his story. The human brain has only so much capacity (well, let's assume there's no magic spell to circumvent that — otherwise, the police/judges are certainly using it themselves so they can detect much more subtle contradictions which non-enhanced human minds would overlook) and thus there's a good chance that if you only ask enough, there will be some contradiction in the story.

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Let's break it down. First, we have to assume that, aside from magic, this world is primarily the same as our current world. And thus, the laws of physics and so forth still apply. Second, let's apply the Occam's Razor here and go with the idea that the simplest of explanations is usually the correct one. Based on those two premises, let's proceed.

Here's what we know. Frank is dead and Alfred was seen with a weapon matching Frank's blood and was also seen dumping a body into the river by multiple witnesses.

Alfred's defense was: It wasn't me, someone placed an illusion there and made it look like it was me.

If I was the prosecutor I would test the following:

  • Alfred's alibi for the time of the murder and for the time of the body being dumped.
  • Any residue from ANY type of spell cast at either the crime scene, upon Frank's body, upon Alfred and upon the suspected murder weapon. I'm assuming spells would leave a finger print and, as such, would be subject to forensic analysis like any other evidence at the crime scene.
  • Fingerprints on the murder weapon. (We already know it tested positive for Frank's blood).
  • Analysis of Frank's body to ensure the murder weapon was, in fact, the knife or something very similar to it.
  • Check to see if there were any defensive wounds on Alfred and/or if Frank has DNA evidence of Alfred under his nails or in his teeth.
  • Alfred's shoe size and shoe type and then check the soil in and around where the body was dumped. My guess is that illusions would either not leave a shoe print, or the print they left would be that of the real person dumping the body. If that doesn't work for your world, then change this as necessary.
  • Check Alfred's house to see if there were any shoes or boots with mud on them and / or with blood from Frank.
  • You specifically said there were no CCTV's, but - since this is a world of magic - does this mean that there is no equivalent to a recording spell? Or maybe Clairvoyance that works in the recent past? Let's see, I think it's called Psychometry.
  • If there's illusion magic, then I'm willing to bet there's some sort of equivalent to a Truth spell. As another guy said above, if Alfred is claiming magic was involved in his case, he needs magic to help prove his innocence. And while Alfred's Fifth amendment also applies to 'Magic without Consent,' his not allowing a Truth spell to be cast on him would weigh heavily with most juries against him. (Although, Alfred's lawyer could potentially use an expert witness to claim that Truth spells are not absolutely reliable, and thus not in his client's best interests.)

While most of this is circumstantial evidence; a lot of it would be clear cut towards Alfred's innocence or extremely difficult to explain away. "And why, exactly, did this illusionary copy of you have your exact boot size and style while carrying Frank's body? In fact, the exact same size and style of boots found downstairs in your basement... covered with mud?"

Sure - this kid of evidence is not exactly the same as having murder weapon with prints. But it's very hard to explain away by anyone - even with something like the illusion defense. In fact, the illusion defense makes it even more difficult because the premise there is someone else carried the body and dumped it and they just looked like you.

Just some thoughts. I hope these help.

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Previous answers deal with how to use the legal system to pierce the illusion or use forensics to prove it. This is how to cope with undetectable illusions without truth magic.

If there is no way to prove that illusions were not used and no truth magic there is still an alternative, a total ban. Society could make it very illegal to use or know illusion magic with high penalties. With a good deal of effort its use could be rendered very rare and thus in most every case the illusion defense could be reliably discounted.

The same also applies to mind control magic

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But then anybody who knew illusion or mind-control magic could "game the system", framing others constantly, always in a different place, killing any witnesses all in one go, etc. – wizzwizz4 Jan 6 at 17:12
@wizzwizz4 yes but the idea is people like that would be so heavily hunted there would be almost none them left. Again this answer deals with undetectable illusions so there is little alternative. – sdrawkcabdear Jan 6 at 18:29
But they can create undetectable illusions... They would be invincible and few would know of their existence. A secret cult, persecuted... they would be able to stay hidden. – wizzwizz4 Jan 6 at 18:38

Magic is a threat to any current legal system. The reasoning regarding these legal systems assume things like, say, the word of experts (experienced / proficient professionals who act as the voice on matter for the judges). Magical procedures should be accepted since otherwise they could taint the entire process leading to an evidence dismissal as being a fruit of poisonous tree (think the hard it is to make a court accept DNA proofs and hidden recording proofs).

For stuff like a murder, you need more than just an illusions test (the defendant claims to been under an illusion and picks a knife which he never used). You must check:

  1. Was the user under the effects of Imperio? (This was a claimed defense in Harry Potter's canon). If the suspected does not remember anything, consider also he being under effects of obliviate.
  2. Was the matter/space correspondence altered so that the suspected actually grabbed a water bottle, and one split-second later he was found with a knife in his hand?
  3. Was he posessed by a summoned spirit? Either by him or someone else.

And questions like that. For that to work, experts should develop metamagic skills (spells that may affect or guess stuff about other spells, in the same way that meta.SE sites discuss about the corresponding SE site; your magic world should support some stuff like this in order to have at least a draft of a legal system). And then we fall into a Petitio Principii: Does metamagic affect itself? Is there a last-word metamagic spell which could unveil the truth about the execution of a metamagic spell (or regular spell) and not be countered/altered anyhow?

Magic is the ability to change the reality somehow. Even if you limit your magic to just violate thermodynamics, it's enough to develop science breaking laws of space and time (e.g. teleport) and would screw your proof system. Even with metamagic, you find yourself in a world where everyone is potentially self-sufficient in power (or at least those who can handle the power).

Think about bitcoins. They are a coin generated by the network itself, with a kind of algorithm (programming could be seen as magic if some laws are respected) belonging to a scheme called Byzantine Fault Tolerance. The same would occur to the magic: the most people uses metamagic to freeze or recover the actually occurred facts (at least 51% of magical skills in the whole world), the most accurate will be the rules. Bitcoin nodes/servers are the wizards here, which process the transactions and maintain the encrypted wallets.

But being that a judge should correlate evidences -by logical reasoning- with facts by stating time, space, and matter being inmutable... What's the relevance of a trial as we state now when those three aspects of reality itself can be mangled? E.g. how would you implement a magic-aware legal system in a country with conflicts like Venezuela? (currently 66%+ people opposes the government and the overall system).

Summary: If the legal system -our current, Roman-based, legal systems- is flawed as it is now many times, and if an evidence corruption can flaw an entire case... How would this system be relevant/accurate when the reality itself is/was/will be mangled? Usually facts... happened. How would you trust any legal system if you can even make (with a combination of magic and our current science status) facts unhappen? There would be no fixed reality to judge.

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Assuming CCTV is influenced by the illusion, we can assume that it would have seen the water bottle as well, instead of the knife. Alternatively, it could have seen the knife and the murder instead of the water bottle that had really been there.

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TH3F4LC0N welcome to the site. This is more a repetition of a point made in the question not really an answer – sdrawkcabdear Jan 5 at 1:37

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