Italian police say a Rome university student has been burned alive by her ex-boyfriend.

A police official, Luigi Silipo's told reporters Monday that in 25 years of investigations he has "never seen such an atrocious crime" as Sara Di Pietrantonio's slaying.

Investigators say the man, who was held for questioning, doused first her car, then the woman with alcohol before dawn Sunday. Prosecutor Maria Monteleone says some motorists drove by as the 22-year-old woman cried for help but no one stopped or called police.

Police say her attacker, a 27-year-old security guard she had dated for two years, caught her as she tried to flee and set her head afire with a cigarette lighter. Investigators say he followed her car, forcing her to pull over on a Rome street.