They treated him like he was a piece of dirt," Jim Chasse said. "Just absolute from the get go."

Chasse's 42-year-old son James was out for a walk in downtown Portland, Oregon, in September 2006 when three police officers spotted what they later described as a "peculiar...dirty" young man.

Eyewitnesses say Chasse, who suffered from schizophrenia, appeared "frightened." And when he ran, they say, he was chased, knocked down and beaten by police.

Chasse told CBS News chief investigative correspondent Armen Keteyian that his son wouldn't hurt anyone. "This is a guy who couldn't lift 35 pounds," Chasse said. "And they say he was struggling."

Video shows Chasse being carried through the jail on his way to the hospital. He never made it. He died from "blunt force trauma to the chest." An autopsy found Chasse was tasered. His ribs were broken in 27 places.

Two officers involved received two week suspensions for failing to ensure Chasse received medical attention after being tasered. None of the officers involved was fired.

"These people are supposed to be peacekeepers when in fact they are raising all kinds of hell," Chasse said.

The Chasse family sued and received a $1.6 million settlement from the city, which admitted no wrongdoing.

But this father wasn't finished. He hired a lawyer to present evidence to the Justice Department that his son's death was part of a pattern of excessive force by the Portland Police Bureau.

A federal law enforcement source says the Chasse case is one of a significant number of incidents that has prompted the Justice Department to investigate police here in Portland for civil rights violations.

WATCH: DOJ Launches Civil Rights investigation

Roy Austin, Deputy Assistant Attorney General for Civil Rights, said "The good officers know who the bad officers are. Everybody knows who the bad officers are."

CBS News has learned that Portland is just one of 20 police departments nationwide that the Justice Department has investigated for civil rights violations in the last year - more than any time in history. Among the allegations: In Newark, a rape. In Seattle, the fatal shooting of a homeless man. In New Orleans, another deadly shooting.

"What we have is a number of departments where the officers are not given the tools that they need to succeed," Austin said. "Meaning they don't have the training. They don't have the supervision. They're not held accountable."

Portland's current political leader, Mayor Sam Adams, told us he welcomed the federal oversight, calling the Chasse case "awful and tragic." He says the city has added new training for officers.

In a statement, Portland's Police Association said "We handle...often explosive situations fraught with risk, with professionalism and compassion."

Still, in the last 20 months there have been two more controversial police shootings - both fatal. Leaving Chasse with little faith in a force created to serve and protect.

"There is nothing I can do," Chasse said. "My son is dead."

CBS News has also learned there were 52 criminal civil right cases brought against law enforcement officers by the Department of Justice last year. That's the highest number of cases in a single year since they started keeping track back in 2000.