The Los Angeles County Coroner's Office identified the men as Pirooz Moussazadeh, 27; his brother Shahriar Moussazadeh, 38; and Bernard Khalili, 27.
Brattson Anatole lives right below apartment 204, where the shootings happened. He said he didn't know the people living above him.
"We overheard some shots, but I thought, 'Those are firecrackers,' you know?" said Anatole. He said he then heard someone running down the stairs.
Detectives said there were no signs of a struggle or a break-in at the apartment.
The Kings Road Arms apartments can only be accessed by residents who have a key. The idea that someone possibly walked in and shot three men has people who live here fearful of even opening their doors.
One resident who didn't want to open her door or be identified said she believes the killers rode with her in the elevator.
"I saw the neighbor who was looking for his mail, and I said 'I'll hold the elevator for you.' He got in. The next thing I knew, another one pops in, another guy pops in, and another guy pops in. And we rode up the elevator quiet, it kind of got quiet. They got off on the second floor," said the neighbor.
She said when the elevator doors opened the men went toward apartment 204. A few minutes later there were gunshots.
"They didn't even sound like gunshots. It was just muted, like in a box," said the neighbor.
Friday, detectives searched the building, dusted the elevator for fingerprints and interviewed residents, trying to gather any information.
Many residents were kept out of their homes as deputies conducted their investigation.
"When I came out of the building, the sheriff said I couldn't go back in," said Albert Ostiz of West Hollywood.
It's a tough case with few leads.
"Obviously we've been working all night long as part of this investigation. I don't even have an idea about motive. Now we're talking about suspect and/or suspects," said L.A. County Sheriff's Sgt. Bill Marsh.
Detectives are seeking the public's help. Anyone with information related to the case was asked to call the L.A. County Sheriff's Homicide Bureau at (323) 890-5500.