NEW YORK (AP) — A man accused of beating four homeless men to death as they slept on the streets of Manhattan's Chinatown has become a suspect in a nonfatal attack about a week earlier, a top New York Police Department official said Tuesday.

At a news conference on city crime stats, Chief of Detectives Dermot Shea told reporters that Randy Santos is under investigation in the Sept. 27 assault of another homeless man sleeping on a waterfront bench along the West Side Highway in Chelsea.

The victim described waking up to find someone beating him with a stick before trying to pick him up and dump him into the Hudson River, Shea said. Investigators have recovered security video that shows Santos in the vicinity around the time of the assault, he said.

"We have him approximately seven blocks away, very clear video of who we believe is Mr. Santos on that evening, and we believe he was responsible for that attack at this point," Shea said.

Prosecutors say Santos, himself homeless, rampaged through Manhattan's Chinatown early Saturday, bludgeoning the four men with a metal rod. Officers responding to a 911 call found him carrying a metal pipe covered with blood and hair near Mulberry Street and Canal Street.

Autopsies concluded that all four died of blunt impact head trauma with skull fractures and brain injury. A fifth man remains hospitalized.

Santos has at least six prior arrests, including two last year on charges he punched a stranger on a subway train and choked another man at an employment agency, police said. He also was arrested in May after allegedly punching a homeless man inside a Brooklyn shelter.

At the news conference, Mayor Bill de Blasio said the attacks should not be viewed as a failure of city efforts to provide more mental health treatment to people living in shelters and on the street.

"We have a very tragic incident here, but not one from what we know so far that could possibly have been predicted from what we saw in this case," he said.

Santos did not enter a plea to murder and attempted murder charges at an initial court appearance. He was ordered held without bail.

Voice mailboxes for Santos' court-appointed lawyer were full and not accepting messages on Tuesday.

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