This makes no sense for the police to conclude the gunman acted alone given the tip that led the police to the person of interest (who suicided alledgedly with same gun).
from the Ronni Chasen wiki:
Beverly Hills Police Department sources stated that Chasen received approximately five gunshot wounds to the chest, which caused her to lose control of the vehicle just after turning from Sunset Boulevard onto Whittier Drive. Police surmised that Chasen's killer was an expert marksman and likely shot her from an SUV or truck that pulled alongside her car. A leaked coroner's report noted that hollow-point bullets might have been used by the gunman.
On December 1, 2010 the Los Angeles Times reported that a man believed to be involved with Chasen's murder committed suicide after being confronted by police at the Harvey Apartments on Santa Monica Boulevard in East Hollywood and that the suspect in Ronni Chasen's slaying had been under police surveillance before he killed himself. The Los Angeles Times reported the man, a convicted felon named Harold Martin Smith, was approached by police in the apartment lobby, at which point he pulled out a pistol and shot himself in the head. On December 6, 2010 it was reported that the man was no longer considered a person of interest in the murder. However, on December 8, 2010 the Beverly Hills Police Department declared its preliminary conclusion that Chasen's murder had been a random act of violence, a robbery attempt turned violent. According to the police, the gun the suspect used to kill himself was the same one used to murder Chasen. Police said they believed the man acted alone and it was in no way connected with road rage – an operating theory the previous week. The big break in the case was a tip through America's Most Wanted – after the suspect began bragging to neighbors that he shot Chasen and got $10,000 for it. The AMW tipster – who wants to remain anonymous – stands to collect a $125,000 reward.---