Orange County District Attorney Tony Rackauckas will hold a news conference at 11 a.m. Wednesday to announce whether his office will file criminal charges against six Fullerton officers.
The FBI has also launched a probe to determine if officers violated the civil rights of Kelly Thomas, 37, during the July 5 altercation.
Tempers flared at Tuesday night's Fullerton City Council meeting against the police chief and several City Council members.
The father of Thomas said he is anxious to see what the autopsy report shows.
"I'm not very hopeful that we're going to get the justice that we're looking for," Ron Thomas said. "We are ready to take it to a federal level."
Officers responding to reports of someone burglarizing cars at a transportation hub in got into a violent fight with Kelly Thomas, who suffered from schizophrenia.
Ron Thomas said his son died from head trauma.
Thomas alleges one officer, Kenton Hampton, was involved not only in the incident with his son, but in two others where he is accused of brutality and false arrest.
Thomas was told he cannot attend the news conference Wednesday.
"My attorney and I should have been invited in and talked with the D.A. first to let us know what's coming down," he said.
Fullerton police along with other law enforcement held training exercises Tuesday that included crowd control tactics.
Thomas wonders if they are preparing for an angry response from the community.
"Whatever is going to be done I think it's going to be enough to really, really upset people," Thomas said. "Why else would you practice riot control with all these different entities?"
Sgt. Andrew Goodrich of the Fullerton Police Department said it was a preplanned training day.
The police department said it doesn't know what's in the report.
"We're awaiting the D.A.'s results, just like the rest of the community is," Goodrich said. "We're not expecting any unrest but we are prepared for any unrest."