A professor at a Long Island college was beheaded outside an apartment building by her son who then jumped to his death in front of a train Tuesday, police said.

The decapitated body of Patricia Ward, a 66-year-old associate professor of language arts at Farmingdale State College's LI Educational Opportunity Center, was found outside the complex on Secatogue Avenue around 8 p.m.

Police say her son, 35-year-old Derek Ward, killed her in their apartment and dragged her onto the street as commuters headed home from a nearby Long Island Rail Road station. She had broken ribs and had been stabbed repeatedly; her head was found 5 feet from where her body lay in the street.

The body was found near a home decorated with Halloween pumpkins, fake cobwebs and a mock graveyard. Witnesses thought it was a Halloween prank.

"I saw what I thought was a head in the street. I saw long, black, straight hair and the head face down,'' said Dale Silverman, a medical editor who saw the grisly scene as she drove home from the train station. "And I did a double-take. And I opened the window and said, 'No, that can't be what that is.'''

Several yards away, "I saw the body, completely straight legs together, hands at its side,'' said Silverman, pointing to still-bloodstained areas of the street several yards apart.

"It looked fake,'' she said. "I thought it was a stupid Halloween prank.''

Less than half an hour after Ward's body was found, police received a report about a man struck by a train half a mile away. Detectives say it was Ward's son, and that he had apparently committed suicide after killing his mother. A knife was recovered from the apartment they shared for three months.

Police say there were no reports of domestic issues at the home prior to Tuesday.

A spokesman at Farmingdale State College, where Ward was employed for nearly three decades, described her as "well-known, well-liked and well-respected."

"The campus is a very sad place today," Patrick Calabria, vice president for institutional advancement and enrollment management at the school, said in a statement.

Police said Derek Ward was unemployed. He was arrested years ago for gun possession and criminal mischief, and had a psychiatric history going back about 10 years. Family members said Derek Ward's mental illness was exacerbated by the recent death of his grandfather.