A homeless man wielding a metal pipe beat four other homeless people to death Saturday in New York, police said.
A fifth man was hospitalized in a critical condition.
Police detained a 24-year-old male as the suspect in the attack in the Chinatown area of Lower Manhattan in the small hours of Saturday.
The victims were apparently asleep when they were set upon, said Michael Baldassano of the New York police department.
"The motive appears to be, right now, just random attacks," he told reporters. "No one was targeted by race, age, anything of that nature."
Every night more than 63,000 people sleep in the New York City shelter system, says the Bowery Mission, an advocacy group.
But nearly 4,000 more sleep on the street, in the subway or in other public areas.
The group says factors causing homelessness include mental illness, substance abuse, lack of affordable housing and problems keeping a job.Two of the men were killed on The Bowery, which cuts through the heart of Chinatown and has for decades been known as New York's skid row. Two more died on East Broadway, the neighbourhood's main street.
The lone known survivor of the attacks was hospitalized in critical condition. Police planned to question him as soon as possible, Baldassano said.
Another homeless man who had slept in the area, Stephen Miller, said he knew one of the victims as kind and quiet.
"No one knew him by name, but we saw him every day," Miller said. "At this point, I'm just sad. This guy never did anything. Just had a life to live. It sucks that he's out here in the rain and everything but it doesn't mean he doesn't have a life to live."
New York City's homeless population has grown to record levels over the past decade, and the homeless remain among the city's most vulnerable residents. Over the last five years, an average of seven have been slain each year.
Mayor Bill de Blasio launched new homeless outreach efforts early in his tenure in an attempt to move more people off the street and into shelters, but the program has faced challenges. City efforts to build more homeless shelters have dragged due to neighbourhood opposition.
De Blasio tweeted Saturday that he's "stunned and horrified by this senseless act of violence against the most vulnerable members of our community."
The attacks happened in one of the few downtown Manhattan areas that has retained its character as a centre for new immigrants, through gentrification has started to creep in lately.
During the day, it bustles with small shops, restaurants and markets doing business in Chinese, as a mix of residents and tourists pack the sidewalks. At night it can be desolate in some sections.
