MIAMI -

The mother of a man who police said chewed off much of the face of a homeless man and was then fatally shot by police said her son is not the monster he has been portrayed to be, WPLG-TV in Miami reported. 

Rudy Eugene, 31, died Saturday after being shot by police. Investigators said he was the nude man seen on surveillance video near the MacArthur Causeway, getting into a fight with Ronald Poppo, a 65-year-old homeless man. 

Video: Surveillance video of attack

Police said Eugene bit off most of Poppo's face. An officer arrived and yelled commands, and then shot Eugene several times, killing him, according to police. 

Investigators said they believe Eugene walked the three and a half miles from Miami Beach after his car was towed, shedding clothing along the way.

It is not yet clear whether the six surveillance cameras along the causeway captured video of Eugene. 

The cause of the scuffle is not clear. Police said they believe Eugene was homeless and theorized that he was in a drug-induced psychosis, but that has yet to be confirmed by blood test results. 

Eugene's grief-stricken family has refuted that theory. 

"I knew my son," said Eugene's mother, Ruth Charles. "Rudy will never, never do something like that." 

"The truth of the matter is my brother would never, my brother would never, be homeless. You know what I'm saying? He would never be homeless," said Eugene's brother. "He had people that love him. He had somewhere to stay. He had somewhere to be." 

"Somebody killed him, and they just go and they dump him," Charles said. 

Family members said they believe Eugene was the victim of violence Saturday, that someone dumped him at the base of the Causeway and that he came to, frightened and feeling threatened by a homeless man near him. 

"When you're awake, you're like a confused patient, like confused. Whoever you see, you go and fight," Charles said. 

"I don't believe he'd walk there butt-naked, 12 o'clock in the afternoon, and nobody see that," his brother said. 

Charles said she does not believe her son was mentally ill. When asked whether her son may have done drugs, Charles said, "To tell you the truth, that I don't know." 

Charles said she does remember Eugene's 2004 arrest. Her husband called police, and Charles told officers Eugene was threatening to kill her. 

"He was angry," Charles said. 

Eugene's brother said Eugene was not angry Saturday morning, when he left his girlfriend's Miami Gardens home about 5 a.m. 

"He seemed pretty calm, what she said. He woke her up to tell her, "I'm going to leave now. I'm going to go see one of my friends.' (He) gave her a kiss, said, 'I love you,' and he left," his brother said. 

Police are awaiting toxicology results. 

Poppo was listed in critical condition at Jackson Memorial Hospital.