The gun that Beverly Hills police believe was used in the slaying of Ronni Chasen was a .38-caliber revolver, according law enforcement sources.

This would explain one of the mysteries surrounding the Hollywood publicist's death: There were no shell casings recovered from the scene where she was shot because in revolvers, shell casings remain in the chamber after firing.

Investigators recovered the revolver at a Hollywood apartment building where Harold Smith killed himself after being confronted by detectives.

Police said preliminary ballistics tests showed that the handgun Smith used to shoot himself in the head was the same weapon that killed Chasen on Nov. 16 as she drove her Mercedes-Benz sedan along Sunset Boulevard after a film premiere.

Authorities have said they believe Smith acted alone in the crime, which they described as a robbery gone bad.

The lack of shell casings had led to some speculation that the shooting was a professional job by a hit man who collected the casings before leaving the scene.

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-- Andrew Blankstein