PHILADELPHIA (AP) _ A young woman was fatally stabbed during an hour-long argument, and her estranged boyfriend jumped to his death from a bridge, officials said.

The man had telephoned the woman's parents to tell them, ''you better get up here,'' and the couple arrived at about the same time their daughter's body was found.

Cynthia Stewart, 20, a business school student, was stabbed at least 12 times Monday by Arnold Walker, 25, at their apartment during the dispute over a breakup in their relationship, police said.

Walker fled after neighbors, alerted by screams, tried to intervene, police said.

''She was screaming 'Help 3/8 Oh God, help 3/8' Then I heard a noise like pounding,'' said maintenance worker Kwabena Nyantaki. ''Most of the tenants heard it all morning.''

Shortly afterward, Walker jumped 40 feet from a bridge onto an expressway, police said. He died of massive head injuries at the Medical College of Pennsylvania Hospital, officers said.

Walker, an employee of the Philadelphia Electric Co., had driven to the bridge in Ms. Stewart's car and the knife used in her slaying was found in the vehicle, police said.

''It was just one of those personal tragedies. It's a shame, too. They were very young people,'' said police Lt. David Reed.

Before the slaying, Walker called Ms. Stewart's parents in Wilmington, Del., told them ''You better get up here,'' then hung up, police said.

Charles Stewart, a Wilmington police officer, and his wife arrived about the same time as police and found their daughter's nude body lying in a pool of blood on a bed, police said.