Could it work?

Roughly paraphrasing Herzfeld's dvd commentary, and my (relatively rudimentary) understanding of law in the USA (very broadly, though I must add that there's even difference from place to place within the US, but typically not in this case), no, the plan absolutely would not work, in the way described.

Before any trial takes place there is (afaik) a hearing to determine if there is evidence enough for the case to be prosecuted. At the same time, among their many tasks, there is an assessment (potentially) by a pyschiatrist or psychologist (or both) of the accused, as to the mental health status of the accused. It's not a case specifically of whether they are guilty or innocent, based on some mental defect or illness, but instead an assessment to determine whether the accused is capable (capable irrespective of their willingness to do so which is a different ball game) of understanding the charges, and assisting/contributing to their own defence.

At that time, if the accused is found not to have the mental capacity to fulfil that requirement, then more likely than not there won't be a trial for the crime itself, but they may be then placed into psychiatric care, as a measure to protect them, and society from them. Should they recover and be able to assist their defence, they may indeed be charged for the crime (statute of limitations permitting, and notably many crimes have no statute of limitations, so they can press charges years after the crime for things like murder), It's possible that some may never be released from the asylum, and live out their days there. So in that case they may not ever have been charged let alone convicted, so they aren't just 'free to go' 10 seconds after some feigned illness, they simply won't be tried

IF it's determined that they can go to trial and assist their defence etc, then they will indeed be prosecuted. Depending on the crime, there are numerous defence strategies and options. They could claim temporary insanity (or whatever it's called elsewhere). This would need to be played out demonstrating that the person did in fact commit the crime, at the time they were under severe emotional distress or having a breakdown, and literally were unable to control their actions. This _might_ be believed, but it would be extremely rare to say the least. There's some research that whilst such behaviours can take place, generally a genuine temporary loss of control lasts a very short time (minutes at most), and will only involve 1 specific act. For example, if some was feeling under attack and then shot someone, then by the time the shots were fired, the gun would be emptied (soon enough).. To actually have the presence of mind to then be aware that the gun was empty, and needed reloadng, and the reloading took place, it would be almost certainly the case that if they truly lost the plot, they'd not be capable of reloading. (reloading a weapon and continuing to fire it, has actually occured in some cases and it damaged the potential of that defence strategy.) .

Juries then have the option (if relevant) that certain incidents where a person was indisputably the person who killed the other party, allow them to be able to retun a not guilty verdict - self defence, necessity, accidental, temporary insanity etc.

Depending on specifics, a trial might just manage to return a not guilty by reason of temporary insanity. (or more prolonged bouts of it). It's possible that at that time they stil might not be released, but ordered into an institution (possibly for life). In that case they aren't considered criminals (in the standard sense of the word) but rather as people with severe mental illness. So they are a patient rather than a convict, and there not as a punishment, but to protect society (and themselves) against possible (or already occuring between the time that the murder was commited and the trial) harm they might not be able to prevent themselves from doing.

Thankfully from what news turns up from around the globe, it seems that as a general rule US courts etc take murder, esp that of an officer _very seriously_ and capital punishment or life without parole is on the table. In Australia (and this is about the only thing that many aussies dislike about our country) it's a little less severe. No kidding, a guy (a youth at the time) and an older accomplice did a string of armed robberies and ended up killing 2 police officers who were staking out likely targets. During investigations, bugs planted in cars and homes picked up candid conversations of them detailing the murder, bragging, joking, and even planning to kill more officers in another location to throw off the scent. The older (thank god) will never be released but believe it or not the younger man was given a lengthy sentence, but the possibility of parole. Ridiculous. Whilst the concept in the movie won't work in the US, it Australia it might nearly be doable (well not really).

The 'other' scenario discussed was the 'artist' who blamed his acts on medication or something, claiming they were prescribed by a pschologist or psychiatrist who then failed to warn about side effects that might affect inhibitions and impulse control. Apparently (again from dvd commentary) this was partly inspired by a real case, and that _would_ be a little more plausible.