The DJ whose tweet led to street chaos on the Hollywood Walk of Fame may face criminal charges.
"We will make a determination about whether there was any criminal behavior," a spokesman said.
There was tension in the air Thursday night as thousands of fans gathered outside Jimmy Kimmel's studio for an outdoor Lady Gaga concert just across the street from where the riot erupted.
As police helicopters circled overhead, Kimmel joked about the rioting.
"It got a little rough. Police fired non-lethal bean bags into the crowd after they refused to disperse which resulted in several minor injuries and a dozen games of hackey-sack," joked Kimmel.
Fortunately, the concert was trouble-free. Lady Gaga even thanked cops in a hand-written note addressed to her fans:
"Kisses to the cops for keeping you safe. Love, Lady Gaga."
And the red carpet was out again at the very spot where police faced down rioters, for the premiere of Rise of the Planet of the Apes.
The movie stars James Franco and Freida Pinto.
"The apes are no longer played by humans in masks. They are created through computer graphics. It's incredibly realistic," said Franco.