PITTSBURGH (AP) _ The state Supreme Court on Wednesday struck down a major portion of Megan's Law, a measure that forces sexual assault convicts to announce their presence in their chosen community.

The court ruled that the law improperly presumes people are guilty by classifying them as ``sexual predators'' for life.

The ruling effectively struck down a provision that allowed communities to be notified when certain sex crime offenders move in. But the court did not touch a portion that requires someone with the less-severe classification of ``sexual offender'' to tell state police, not the community, where they are.

Every state has some version of Megan's Law, said Ronald Chen, associate law dean at Rutgers University in Newark, N.J. He said the law has been revised to meet constitutional tests, and has been upheld by federal courts.

Defense attorneys say the 1995 law _ a version of one in New Jersey named for a girl who was raped and killed by a convict in her neighborhood _ improperly reverses the burden of proof in criminal cases, which presumes innocence.

The predator classification requires the convicts to register with police on their whereabouts once they leave prison. Police then notify the communities.

Supreme Court Justice Stephen Zappala said he found the law's presumption that a person is a sexually violent predator ``constitutionally repugnant.'' The determination is made by a judge.

Crimes for which a person can be classified a ``predator'' include kidnapping, rape, forcing a child into prostitution or crimes involving obscene pictures, indecent assault or spousal sexual abuse.

While the 6-1 ruling invalidates the community notification provisions of the law for predators, the court did not touch the portion that requires someone with the less-severe classification of ``sexual offender'' to tell state police where they are for 10 years. Police do not notify communities of the presence of ``sexual offenders.''

In a dissenting opinion, Justice Ronald Castille said the law ``is a mere sentencing scheme and does not create a separate criminal offense'' that would violate the U.S. Constitution.

The district attorney whose case resulted in the Pennsylvania court's ruling said he may appeal to the U.S. Supreme Court.