Assuming that the above can be established by admissible evidence, that sounds like a case for first degree murder, and probably various other crimes as well. In some jurisdictions there is a specific crime of "Murder for hire" which might also apply if available on the jurisdiction where this occurred.
A comment mentions a possible insanity ...
These charges aren't the same offense. They are three different offenses, all of which arise from the same conduct.
Imagine throwing a grenade in a building because you saw a police officer about to discover evidence connecting you to a crime. I think most people would agree that there's no reason you could not be charged with murder, arson, and tampering ...
There is no statute of limitations on murder
This is true of other serious crimes as well like sexual assault, war crimes, genocide etc.
The person can be charged now, 10 years from now, 100 years from now. Assuming they are still alive, of course, you can’t charge dead people.
As a practical matter, historical crimes are more difficult to prosecute due to ...
Under 10 USC 843(a), i.e. Article 43 of the UCMJ,
A person charged with absence without leave or missing movement in
time of war, with murder, rape or sexual assault, or rape or sexual
assault of a child, maiming of a child, kidnapping of a child, or with
any other offense punishable by death, may be tried and punished at
any time without limitation.
There was a case like that in 2010 in germany
tl;dr synopsis of the German article:
The police raided the private home of an alleged member of a criminal gang. This was performed as a no-knock raid. The police officers did not announce themselves as such when they started to break open the door.
The suspect had reason to believe that a rival gang was ...
Has there ever been a successful defense based on "self-defense" in a case of a person charged with killing an on-duty police officer?
Detective Constable John Fordham was on duty when he was killed by Kenneth Noye, a career criminal, who was found not guilty of his murder by successfully claiming self-defence.
John was ...