At about 6 p.m., the LAPD responded to a call of shots fired on the 5600 block of Santa Monica Boulevard. At the time of the shooting, Beverly Hills Police Department detectives were on scene conducting a follow-up investigation.
The man's identity has not been released. It's unclear how he is connected to the shooting. Beverly Hills police said the man "was a person of interest only."
The man shot himself in the lobby.
"They attempted to talk to the suspect. When they did, the suspect produced a handgun and there was a self-inflicted gunshot wound," said Capt. Kevin McClure of the LAPD. "The suspect was pronounced at the scene."
Neighbors said they heard loud noises.
"On the first floor right below the steps, I saw a big splatter of blood," said neighbor Terri Lyn Gilpin.
Chasen, 64, was found shot dead in her Mercedes-Benz in Beverly Hills on her way home from a movie premiere after-party Nov. 16.
A leaked coroner's report raised more questions, including whether the gunman was a hired killer.
Chasen was a powerhouse publicist in the movie industry and her closest friends say she could work miracles because of her contacts.
"She was the Elizabeth Taylor of public relations," said Chasen's friend Helaine Ross. "People wanted her because they knew that she knew everybody."
ABC News has seen a copy of the initial coroner's report, which is now under a security hold.
The report says one bullet was recovered from her back while at the hospital and is possibly a 9mm hollow-point.
Chasen received three apparent wounds to the right-side breast/chest area and two apparent gunshot wounds to the right shoulder.
Detectives suspect the gunfire came from an SUV or a truck pulling alongside her car.
Detectives say it appears the shooter was an expert marksman.
"Normally they turn that gun sideways and this is something that's done with some skill," said former L.A. County Sheriff's Dept. homicide detective Gil Carrillo. "I'll be honest with you: I've carried a gun for 38 years and had to qualify quarterly. I don't know that I could shoot and hit that mass like that."
Carrillo was a homicide detective for more than 20 years in Los Angeles.
"My gut tells me that somebody contracted someone else to kill the victim," said Carrillo.
The location has been called the "Bermuda Triangle" of Beverly Hills. It's near the area where Howard Hughes survived a plane crash in 1946 and Bugsy Siegel was gunned down on the street.
