The video shows the attacker, identified as 31-year-old Rudy Eugene, walking naked on the sidewalk near the Biscayne Boulevard exit Saturday afternoon before he encounters his victim, 65-year-old Ronald Poppo.
Eugene appears to struggle with Poppo, throwing him on to the sidewalk as cars and bicyclists speed past and a Metromover car passes by overhead.
As Eugene gets Poppo on the ground, he stands over him and starts ripping his clothes off, while Poppo tries to fight back.
The attack continues for several minutes as Eugene appears to drag Poppo under the Metromover track and just out of the camera's view.
Three bicyclists are seen passing right by the two men, and the driver of a white car slows down on the off ramp before leaving. Much of the attack couldn't be seen, however, due to the waist-high barrier wall separating the path from the roadway.
Police say five different passersby called 911 to report the incident, including a Florida Department of Transportation Road Ranger. The first call, from a motorist, was routed to the Florida Highway Patrol before it was transferred to Miami Police, according to the Herald.
The Road Ranger, who also called 911, even tried to get Eugene to stop by calling to him over a loudspeaker.
About 16 minutes after the attack began, a patrol car comes into view of the camera driving up the the ramp against traffic. The car circles around before parking next to the scene.
An officer, identified by the Herald as Jose Rivera, gets out and approaches the two before drawing his firearm and walking under the tracks and out of the view of the camera.
Rivera opened fire, killing Eugene. Authorities say he had savagely attacked Poppo's face and had growled at the officer when he told Eugene to stop.
"Seventy-five to 80 percent of his face was missing, and he was actually swallowing pieces of the man's face," said Armando Aguilar, president of Miami's Fraternal Order of Police. "He growled at him like a wild animal and kept eating at the man's face."
Poppo was taken to Jackson Memorial Hospital, where he remains in critical condition. Miami-Dade Police said they are trying to find the next of kin for Poppo, who is homeless, but have not yet located them.
Eugene's brother told NBC 6 Wednesday that he was a little shocked when he heard about what happened.
“Pretty uncharacteristic of him. It was real weird – kind of mixed emotions, I think,” said the brother, who only gave his first name, Thompson. “Through the whole thing I was mostly thinking about my mom.”
Thompson described his older brother as a caring person who took good care of his mother, who lives in North Miami. He said Eugene was like a typical brother.
"You have your agreements, your disagreements. You know, like, he teaches you some things, you teach him some things, and you know, helps you develop into the kind of person you are going to become eventually," he said.
Records showed Eugene was arrested for a variety of charges between 2004 and 2008, including battery and trespassing. He also served time for selling and possessing marijuana.
When he was arrested by North Miami Beach Police in 2004 and charged with domestic battery and assault, an officer wrote in an incident report about the victim, "She told me that her son had broken items within the home and pushed her out of the kitchen area."
“Thank God your (sic) here. He would have killed me," his mother told the officer, according to the incident report.
She said that before the officer's arrival, Eugene told her, "I'll put a gun to your head and kill you," the report says.
School officials said Eugene attended North Miami Beach Senior High School for his sophomore and part of his junior year. He left there and went to Miami Norland Senior High for the rest of his junior year and played football at North Miami where he graduated in 2000.
Eugene, who was an athlete, eventually married Jenny Ductant, who was also a student at North Miami Beach Senior High 13 years ago, but they divorced in 2007, county records and school photos show.
A former classmate of Eugene's at North Miami Beach Senior High said he is a very different person from the flesh-eating monster he's being called.
"Drugs did this to him. Drugs took over a person we knew as a beautiful person," former classmate Victoria Forte told the South Florida Sun-Sentinel.
Police haven't confirmed whether drugs played a role in Saturday's attack. No evidence of drugs or paraphernalia were found at the scene and toxicology tests on Eugene's blood will take several weeks, police said, according to the Herald.
Authorities say Eugene had been in Miami Beach for Urban Beach Weekend shortly before the attack and that his car, a purple 1995 Chevrolet Caprice, was towed after it was parked illegally at 1100 10th Street.
Friday night, Eugene had been with his girlfriend in Miami Gardens, where she said he was acting strangely before he left in his car. He later called her and told her his car had broken down, police said.
Poppo, meanwhile, also has a record of arrests in Miami-Dade dating back to the 1970s. Of his two dozen arrests, eight were for felonies including aggravated assault, aggravated battery and burglary. But no action was taken on most of them, and Poppo was only convicted on one of the felony charges, for resisting an officer with violence in 2005, the records said.
Court records indicate he was already on the Miami streets in 1976, and showed that he was hospitalized in January of that year with a gunshot wound.
Homeless people said Poppo frequently came to the restroom facility on the north side of Watson Island, about a mile from where he was attacked.