He hides behind the Twitter handle "OPFullerton_," won't give his real name and communicates only by email.
The unidentified 24-year-old man said his goal is to draw attention to what happened to Kelly Thomas, the mentally ill homeless man who was allegedly beaten to death by Fullerton police July 5 near a bus station.
"We're not seeing any progress really, and things need to be taken to the next level," said the man.
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The first level was using Twitter to reach out to followers to join the weekly protests outside the Fullerton police department. He said he hopes the next level will be to open a dialogue with the Orange County District Attorney who is investigating the case.
"We're not afraid to say what we're thinking because it won't affect us personally," he said. "We'll keep shouting."
Since late July, the Saturday rallies have been mostly peaceful. But last week, protesters spilled out onto Commonwealth Avenue, blocking traffic and upsetting merchants.
Ron Thomas, Kelly's father, said he understands people are angry, even people he's never met such as the organizers of Operation Fullerton.
Thomas said he speaks to the acting police chief every Friday before the weekend protest.
"If we just coordinate with the police, we can do anything we want out there, but we have to stay within the laws," he said.
Correction: An earlier version of this story incorrectly pointed to the wrong Twitter account. The correct user name is "OPFullerton_."