By Matthew Davis
BBC News, Washington
A loophole in US law may allow people to get away with any major crime within a 50-square mile "zone of death" in eastern Idaho, according to a Michigan law professor.
A small swathe of Idaho could be the venue for the perfect crime
This lawless oasis is said to exist on the edge of Yellowstone National Park because of a poorly drafted statute in the Sixth Amendment to the US Constitution.
Criminals are entitled to be tried by a jury drawn from the state and legal district they committed their crime in, the constitution says.
But, argues Prof Brian C Kalt, while Yellowstone comes entirely under the district of Wyoming, small parts of it spill into the states of Montana and Idaho.
"Say that you are in the Idaho portion of Yellowstone and you decide to spice up your vacation by going on a crime spree," Kalt writes in a forthcoming paper for the Georgetown Law Journal.
"You make some moonshine, you poach some wildlife, you strangle some people and steal their picnic baskets.
"You are arrested, arraigned in the park and bound over for trial in Cheyenne, Wyoming, before a jury drawn from the Cheyenne area.
"But Article III [Section 2] plainly requires that the trial be held in Idaho, the state in which the crime was committed.
"Perhaps if you fuss convincingly enough about it the case would be sent to Idaho.
"But the Sixth Amendment then requires that the jury be from the state - Idaho - and the district - Wyoming - in which the crime was committed.
"In other words, the jury would have to be drawn from the Idaho portion of Yellowstone which, according to the 2000 Census has a population of precisely zero.
"Assuming that you do not feel like consenting to trial in Cheyenne, you should go free."
No criminal defendant has ever broached the subject of the professor's loophole.
And there may be one or two holes, he admits.
It would be hard to limit your criminality to the specific area - meaning you could face conspiracy charges from the state you entered the park from.
Equally you could be charged with lesser offences that do not warrant a jury trial.
"The courts may or may not agree that my loophole exists," he says. "And in any case this essay is not intended to inspire anyone to go out and commit crimes.
"Crime is bad, after all. But so is violating the Constitution.
"If the loophole does exist it should be closed, not ignored."
Criminals have got away with murder before in England, the professor says, but not since 1548 when the law was changed.
Before then it often happened that a killer would strike in one county, but avoid punishment by ensuring the victim died across the county line, he says.
English juries could only consider crimes that occurred in their own county, so no jury could find the killer had committed all elements of murder.