Washington, D.C. ? The Supreme Court said Thursday that a convicted rapist has no constitutional right to test biological evidence used at his trial in Alaska years earlier, leaving it to the states to decide when prisoners get access to genetic evidence that might prove their innocence.

In a 5-4 vote, with the conservative justices in the majority, the court said it would not second-guess states or force them routinely to look again at criminal convictions.

William Osborne, convicted in a brutal assault on a prostitute in Alaska 16 years ago, sued for the right to test the contents of a blue condom the victim says was used by her attacker. A federal appeals court said he had a right to conduct the test.

Alaska is one of only three states without a law that gives convicts access to genetic evidence. The others are Massachusetts and Oklahoma.

Testing so far has led to the exoneration of 240 people who had been found guilty of murder, rape and other violent crimes, according to the Innocence Project, which works to free people who were wrongly convicted.