FULLERTON, Calif. -- In the nearly two decades since his son descended into madness, Ron Thomas has worried every day that the schizophrenic 37-year-old would die of exposure or illness on the streets. He never imagined the end would come in a violent confrontation with police.
The death last month was the end of a trajectory that began when Kelly Thomas was in his early 20s and started showing the first signs of what would later be diagnosed as schizophrenia: he shuttled between addresses, preferred to sleep on the floor and stopped showering.
In treatment, Thomas did well and was able to hold down a job -- but when he stopped taking his pills, he disappeared onto the streets. He racked up an array of charges, from public urination to assault with a deadly weapon, and alarmed his parents with his bizarre behavior.
"My daughter and I have talked for years that we'd get the call that something had happened to him, whether it was from organ failure because he's not drinking enough fluids or the elements or maybe gang activity," said his father, Ron Thomas.
Last month, he was sitting on a bench at the Fullerton Transportation Center, a hub for buses and commuter trains where homeless people congregate, when six police officers arrived to investigate reports of a man burglarizing cars nearby. Police said he ran when they tried to search his backpack and that he resisted arrest.
The incident was captured by a bystander with a cell phone, and bus surveillance tape released Monday showed agitated witnesses describing how officers beat Thomas and used a stun gun on him repeatedly as he cried out for his father.
On the cell phone video, a man can be heard screaming over a fast, clicking sound that those on the tape identify as a stun gun being deployed.
A male witness says the man, identified as Thomas, was sitting on a bench when he was approached by two officers and ran from them. The man says police used a stun gun on Thomas six times.
"They caught him, pound his face, pound his face against the curb ... and they beat him up," the man said. "They beat him up, and then all the cops came and they hogtied him, and he was like, `Please God! Please Dad!"'
On the day of the beating, bystanders said Thomas was approached by two officers and ran from them.
Witnesses say the attack was unprovoked, CBS News Correspondent Ben Tracy added on "The Early Show."
Tracy reported in surveillance footage from a city bus, one passenger described the scene saying, "They were pulling his hair, kicking the (expletive) out of him. And he's all full of blood."
Another witness said, "...And then they caught him, pound his face against the curb, where it's red, and they beat him up."
Thomas was taken off life support five days after the July 5 altercation. His father said Wednesday he was stunned when he learned police officers caused his son's severe head and neck injuries.
"When I arrived at the hospital to see him, I honestly thought that gang bangers had got a hold of him like the cowards sometimes do and just beat him with a baseball bat in the face," he said. "Immediately my thoughts were to get with Fullerton police ... and I didn't learn until a certain amount of hours later the truth. That put me in absolute shock."
Thomas father, Ron Thomas, told CBS News, "If you or I did this, we'd go to prison for murder. That's exactly what needs to happen to these (sic) group of rogue officers. They need to go to prison for murder."
A police spokesman, Sgt. Andrew Goodrich, said the case was an isolated incident.
"We have a good department full of good individuals," he said. "We've made more than half-a-million law enforcement contacts over the past 4.5 years ... This is the only instance of this kind that's happened."
Goodrich said officers receive training on how to deal with the mentally ill and the homeless. But an attorney representing the department, Michael D. Schwartz, said that "public perception of officers' trying to control a combative, resistive suspect rarely conform to those officers' training, experiences, and what those officers were experiencing at the time or reality."
The revelations have caused growing outrage in this quiet college town. More than 70 people spoke at the City Council meeting Wednesday, and a city councilwoman called for the resignation of the police chief. Thomas' father and others were planning a protest outside the police station this weekend, the second in as many weeks.
"My son needs a voice," he said. "Now, the people have become Kelly's voice and, yeah, I'm leading the charge."
Before the City Council meeting Ron Thomas said, "Listen to my son beg these officers, 'Please, please, God, I'm sorry, I'm sorry.' And then, the last words of his life. 'Dad. Dad.' I want you to hear that the rest of your life like I will.'"
Kelly Thomas was an outgoing child who loved to play the guitar, participated in Boy Scouts and Cub Scouts and aspired to be a wildland firefighter, said his father, who raised him alone after he and Thomas' mother divorced.
After his diagnosis, he went to a live-in facility that provided meals and monitored his medication, his father said. Thomas was able to hold down a job at a gas station and then a printing facility and even started to train with the California Department of Forestry and Protection.
But each time he began to improve, he stopped his medications and wound up back on the streets, moving between Yorba Linda, Placentia, Fullerton and Cypress -- all places where he had once lived or had family and friends. One of the hardest parts of his death has been hearing their son described as homeless, the father said.
"That's the heartbreaking part for all of us. We all have ideas of what we'd like our kids to be like and to do in life. With Kelly, we didn't get to realize that and it constantly broke our heart," his father said. "Kelly wasn't homeless at all, he had so many homes, but he wanted to be a drifter and he did."
Life on the streets led to criminal charges.
He pleaded guilty to assault with a deadly weapon other than a firearm in 1995 and since 2004 has had a string of arrests for a host of lesser crimes including public urination, trespassing, battery, unlawful camping, petty theft and vandalism. He racked up traffic violations for jaywalking and failing to obey traffic signals.
His mother sought a restraining order against him in December 2010 after he refused to leave her front porch, took off his clothes and urinated by the front door, according to court papers. In the same court papers, his mother alleged that Thomas grabbed her by the throat when they shared an apartment, although it was unclear when the incident occurred.
The family said they sought the order to try to get him into treatment as his behavior spiraled out of control.
The police department has turned over the investigation to the district attorney's office and placed on paid administrative leave six officers involved in the beating. The FBI also launched a probe into whether the officers violated Thomas' civil rights in the incident.
People with untreated mental illness make up about one-third of the nation's 600,000 homeless, said Kristina Ragosta, legislative and policy counsel for the Treatment Advocacy Center.
More needs to be done by police departments to train officers in how to recognize symptoms and deal with people with mental illness, said Elaine Deck, the senior program manager at the International Association of Chiefs of Police.
Sometimes, an untrained officer can make a situation worse, she said.
"Handcuffing them may escalate the behavior where the officer may think they are trying to calm the person," Deck said. "They may not know that this may actually escalate a response."