A jilted boyfriend burned his university student girlfriend alive after she dumped him, Italian authorities have said.
Sara Di Pietrantonio, 22, died in Rome on Sunday after being attacked by Vincenzo Paduano, 27, prosecutor Maria Monteleone told reporters.
After initially setting fire to her car, Paduano allegedly chased her down the street as she fled before catching up and setting her ablaze.
Investigators said Ms Di Pietrantonio's attacker used a cigarette lighter to set her 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, an officer on the case.
Paduano is now being held on suspicion of premeditated murder, officers said.
Having first denied the killing, the suspect allegedly confessed.
"He couldn't accept the fact he was left by her when she ended the relationship", Mr Silipo said.
Investigators said Paduano, a security guard who had dated the victim for two years, initially followed her car.
He then forced Ms Di Pietrantonio to pull over on a street in the outskirts of Rome before he killed her.
A surveillance camera in the area captured some of the events, including cars that apparently passed by while the woman screamed for help.
Ms Monteleone added that if passers-by had helped, the woman's life might have been saved.