ROME — A Rome university student was burned alive by her ex-boyfriend after she left him, authorities said Monday – a slaying one investigator called the most atrocious crime he has seen in his career.

Sara Di Pietrantonio, 22, died before dawn Sunday after Vincenzo Paduano, 27, set her car afire, prosecutor Maria Monteleone told reporters. He then chased her after she ran out of the car, setting her ablaze when he caught up with her, authorities said. Investigators said her attacker used a cigarette lighter to set Di Pietrantonio’s face on fire after dousing her with alcohol.

“I can say that in 25 years in this work I have never seen something so atrocious,” said Luigi Silipo, the lead police official in the investigation.

Paduano was being held for investigation of premeditated murder, Monteleone said.

The suspect first denied killing the woman, but after eight hours of interrogation, confessed to killing her, Silipo told reporters.

Paduano “didn’t accept being abandoned” by the woman, Monteleone said. “He organized, he planned the aggression,” the prosecutor said.

Silipo said the suspect walked off his job as a security guard about 3 a.m. and waited outside the home of Di Pietrantonio’s current boyfriend. Then, after the woman left the home and drove off by herself, Paduano followed her in his car, eventually forcing her car to the side of the road.