LOS ANGELES (CNN) -- The father of a homeless California man who died after being beaten by Fullerton police officers filed a wrongful death lawsuit Thursday against the city, its police chief and the six officers allegedly involved in the fatal incident.

The lawsuit filed by Frederick Ronald Thomas Jr., 55, of Cypress, California, also alleges assault and battery, negligence and civil rights violations in the death of his son, Kelly James Thomas.

The suit, filed in Orange County Superior Court one year after the beating, seeks more than $25,000 in damages.

Kelly Thomas, 37, a lifelong resident of Fullerton, was shirtless and carrying a backpack, and was wearing long pants and slippers, when Fullerton police were called to investigate a "homeless" man looking in car windows and pulling door handles of parked cars at the city's bus depot last July 5, the lawsuit said.

A security camera at the downtown bus depot provided 16 minutes of video of the officers questioning and then beating Thomas, who was schizophrenic.

An anniversary vigil was scheduled to be held Thursday evening at the Fullerton depot.

Two of the officers have been charged in the beating death and were ordered in May to stand trial.

Officer Manuel Ramos is charged with second-degree murder and involuntary manslaughter, and Cpl. Jay Patrick Cicinelli is charged with involuntary manslaughter and felony use of excessive force.

Both have pleaded not guilty.

Ramos, 37, a 10-year veteran of the police department, would face a maximum sentence of 15 years to life if convicted, authorities said. Cicinelli, 39, a 12-year Fullerton police veteran, would face a maximum of four years in prison if convicted.

"The murder of Kelly Thomas was the inevitable result of the culture of corruption and deliberate indifference within the City of Fullerton Police Department," the lawsuit alleges. "The city's police department has a longstanding reputation of running roughshod on its citizens' constitutional rights, ignoring citizen complaints and issuing no discipline to officers accused of wrongdoing," the lawsuit claims.

Fullerton police spokesman Sgt. Jeff Stuart said the department hadn't yet reviewed the lawsuit and didn't have a comment Thursday.

Recently, Thomas' mother, Cathy, received $1 million from Fullerton's insurance reserves in an agreement to settle her claim against the city in her son's death, according to a city statement. Cathy Thomas, who's divorced from Frederick "Ron" Thomas, released the city and its police officers from all potential claims, the city's statement said.

Garo Mardirossian, the attorney in Ron Thomas' suit, told reporters Thursday that he also represented Cathy Thomas at one point. He declined to comment on her settlement agreement.

Meanwhile, Ron Thomas told reporters at Thursday's press conference that he's considering running for mayor of Fullerton.