MIAMI — Three bicyclists pedaled through the bloody scene where a naked Rudy Eugene attacked a nude homeless man, biting into his face alongside a busy causeway before a police officer fatally shot him, new surveillance video shows.

The nearly 18-minute attack Saturday in the shadow of The Miami Herald headquarters was captured by the building’s security cameras. The newspaper posted the uncensored video online late Tuesday.

Police have released few details about what may have led 31-year-old Rudy Eugene to attack Ronald Poppo, 65, on the causeway that connects downtown Miami with Miami Beach.

In the Herald video, a naked Eugene walks west on the sidewalk alongside an off-ramp of the MacArthur Causeway, which connects downtown Miami with Miami Beach.

A bicyclist speeds past Eugene just as he turns to something in the shade, in an area obscured by the tops of palm trees.

After a couple minutes, Eugene rolls Poppo’s body into the sun and begins stripping off his pants and pummeling him. Later, the footage shows Eugene pull Poppo farther up the sidewalk. Though the view is partially obstructed by the Metromover tracks above, Eugene appears to hunch over and then lie on top of Poppo.

The footage shows a bicyclist slowly pedaling past the men about halfway through the attack, followed by a car slowly driving on the shoulder of the ramp. Cars regularly pass by the scene from the beginning of the attack, but their view is likely obstructed by a waist-high concrete barrier.

Two more bicyclists cross the scene before a police car drives the wrong way up the ramp nearly 18 minutes into the attack.

An officer gets out of the car and appears to do a double-take at the scene before pulling out his gun. He fatally shot Eugene, apparently within a minute of arriving, but the shooting is obscured from view by the tracks.

One bicyclist, Larry Vega, told Miami television station WSVN that he saw the attack and flagged down the officer.

“The guy was, like, tearing him to pieces with his mouth, so I told him, ‘Get off!’ ” Vega said. “The guy just kept eating the other guy away, like, ripping his skin.”

Vega said the officer repeatedly ordered the attacker to get off. Eugene just picked his head up and growled at the officer before continuing to maul his victim, Vega said.

The officer shot Eugene, but he just kept chewing, Vega said. The officer fired again, killing Eugene.

Miami police have not released any 911 calls about the attack. The Miami-Dade County medical examiner declined to provide any information until after the autopsy, which was scheduled for Tuesday. It could be weeks before the results of toxicology tests are available.

Poppo remained hospitalized Wednesday.

“He had his face eaten down to his goatee. The forehead was just bone. No nose, no mouth,” said Sgt. Armando Aguilar, president of the Miami Fraternal Order of Police.