Dozens of officers patrolled the area on motorcycles, in squad cars and on foot. The massive LAPD presence in Westwood Village was in response to rumors on social media that so-called flash mobs might engage in criminal behavior in the area.
At least one person taking part in the event was captured on home video being taken into custody.
Westwood's safety ambassadors notified business owners after receiving the police alert about the potential mobs. Some businesses closed their doors early Thursday.
"I understand that people are angry about the trial, but I don't understand responding to that with a mob scene," said Tamar Schaap, an employee at Rocket Fizz.
In Long Beach, police say over 100 people participated a in a bash mob on July 9 in the city's Pike area. Patrols are being beefed up in preparation for another possible disturbance on Friday.
"They run into the Pike area and just do property damage. They steal from businesses, and in some cases, they were able to attack innocent people," said Sgt. Aaron Eaton with the Long Beach Police Department.
There have been other flash mob crime sprees across Southern California in recent days. On Thursday, San Bernardino police made some arrests after a group of young people attacked pedestrians and vehicles. On Wednesday, some juveniles in Victorville were arrested for unlawful assembly.
On Tuesday night, several teenagers and young adults went on a rampage in Hollywood, robbing businesses and people on the streets.