Riddle

It happened out of the jurisdiction of the court?

They'd already been tried for the murder of that person? (i.e. - no double jepardy?)

Oh, it's not murder, but an accident. . . .

Perhaps the person who ran in saw that the first person had killed somebody else in the car. Or were in the process of killing. That way, the near-victim would be a witness, and had his/her life saved.

One easy answer: Conjoined-twins.

Conjoined-twins are a staple of lateral thinking puzzles so it is worth remembering this. Lateral thinking frequently preys on your preconceptions and one common preconception is that the individual in a riddle is not joined to another. ;-) Another possible misconception is the "2", nothing indicates that there are only those two.

I think this one has been mutated from it's original form. There isn't enough info to do more than guess. Rushing into the compartment is what caused the death but it was an accident?

Edit 1: Craven, is that your strange way of saying you don't know the answer?

The answer is known by a friend of mine,
As far as I know...
It wasn't an accident.
And it wasn't double jeopardy.

I keep thinking along the law path aswell, but it seems to be getting me nowhere!!

Thanks for the tip ADRIAN, I'll check up on any more info.
Thanks again for your help guy's!
Please keep working on it!

No, the answer I gave works perfectly. Lateral thinking puzzles have many answers.

the other person is still alive, it was only attempted murder since THEY both went to court meaning that both are alive and well. if that doesn't work I give up.

You should probably give up, as the question explicitly states that the person killed the other person.

Craven, you've got me confused. Do you mean the conjoined twins are in one compartment and the rusher-in is in another? Does one twin kill/maim the other, causing the scream?

sorry to be so dense tonight...

Many "person clearly murdered, but was not jailed" lateral thinking puzzles are based on the premise that the killer was a conjoined twin and could not be jailed because of the attached and innocent twin.

Aaaaah, the light dawns. Thanks!

My guess would be that one was a cop who was trailing a suspected serial killer, and he/she chanced to catch him/her in the act this time. To 'know one another' does not necessarily mean that they know one another socially.