(LOS ANGELES) -- Beverly Hills police believe they have a solid theory behind who murdered Hollywood publicist Ronni Chasen, putting an end to the Hollywood mystery.
The gun used to kill Chasen most likely is the same one used by person of interest Harold Martin Smith to kill himself last week, according to preliminary police ballistics tests.
"Preliminarily, we believe Mr. Smith acted alone. We don't believe it was a professional hit," Beverly Hills Police Chief David Snowden said.
Despite coverage that has speculated Chasen was killed as part of an elaborate plot, police now believe Smith, 43, an ex-convict, simply rode a bicycle alongside Chasen's Mercedes Benz and opened fire as she waited to make a left turn off Sunset Boulevard.
"We believe it was a random act, and we believe Mrs. Chasen was going to be the victim of a robbery," Beverly Hills Police Sgt. Mike Publicker said.
Chasen, 64, represented A-list movie stars and promoted some of Hollywood's top films. She was on her way home from the premiere of Burlesque on the night of Nov. 16 when she was killed.
Andrew Blankstein, a reporter for the Los Angeles Times, said the Beverly Hills Police Department remains cautious despite what seems to be a break in the case.
"They're not saying that this is a closed case, and one of things that they're going to be looking…for is additional forensic material at the scene, as well as, one of the things that we've heard is that they were examining videotaped surveillance from the neighborhood. So does that surveillance show Mr. Smith either around the crime scene or on his way to the crime scene on his bicycle," Blankstein said.
Skeptics who have followed the case closely might find it hard to believe that one man on a bicycle could carry out this killing.
Copyright 2010 ABC News Radio