Vanzandt was last seen on a city security camera heading east, away from the waterfront, around 11:30 pm accompanied by an unidentified group.
"We're trying to locate those people who might have been with him," Tyler Vanzandt said. "No one's come forward to say something. That's the biggest help we could get if one of those people would come forward. It would let us get some idea of what he was doing."
The Hermosa Beach police are currently investigating.
"It's not necessarily suspicious circumstances, like foul play, but the fact that he's been gone so long," police Sgt. Robert Higgins told the Los Angeles Times. "He is a father, and obviously it's concerning for him to disappear for this much time."
Vanzandt was out with a group of friends waiting to get into the bar American Junkie. He left the group about 10:15 pm to go to a near-by liquor store. Tyler Vanzandt said security cameras showed his brother purchase something from the store, then wander around the area for a bit, before meeting up with the group of unidentified people and walking off into the neighborhoods surrounding the pier area.
Phone records show that Vanzandt's phone died at 10:30, and has been no use in the search, Tyler Vanzandt said.
Vanzandt lives in Lancaster, Calif., and was in the area for a weekend trip, his brother said. His car was left at the hotel he was staying at, and had not been touched when police found it.
Anyone with information is asked to contact Hermosa Beach Police Detective Joshua Droz at 310-318-0334 or e-mail him at firstname.lastname@example.org.