The suspect, Randy Rodriguez-Santos, 24, was detained shortly after police responded to reports of the attacks around 2 a.m. on Saturday and discovered other victims in the Manhattan neighborhood who survived the rampage, authorities told ABC station WABC in New York.
Police said Rodriguez-Santos is homeless and has a lengthy criminal record that includes 14 arrests.
He is charged with murder, attempted murder and unlawful possession of marijuana stemming from the Chinatown killings. He is being held without bail.
Following his arrest, Rodriguez-Santos underwent a psychiatric evaluation, police said.
"The motive appears to be, right now, just random attacks," NYPD Deputy Chief Michael Baldassano, head of the Manhattan South Detectives, said during a news conference on Saturday.
Baldassano said investigators have found no evidence that the victims were "targeted by race, age, anything of that nature."
The victims killed in the attack ranged in age from 48 to 83, police said. Their names were not immediately released pending notification of their relatives.
The victims appeared to be sleeping when the attacks occurred, Baldassano said. Three of the victims were found on East Broadway, while another was found on Bowery, according to police.
All four were pronounced dead at the scenes, police said.
Police responded to reports of an assault around 1:50 a.m. and discovered an unconscious man in his 60s lying in the street on Bowery "with severe head trauma," Hughes said. He was pronounced dead at the scene.
Another man, who also sustained head injuries, then approached the police and was taken to New York-Presbyterian/Weill Cornell Hospital in critical condition, police said.
Witnesses told police they saw a man striking the victims with a metal object numerous times. An officer came across the suspect who has still carrying the pipe with fresh blood and hair on it, according to the criminal complaint.
After searching the area, police found Rodriguez-Santos, who matched the description of the attacker provided by witnesses. Rodriguez-Santos was initially detained as a person of interest.
The heavy metal pipe believed to have been used in the attacks was recovered near the scene, according to Hughes. Police later said the pipe weighed about 15 pounds.
Police are asking anyone who may have seen the assaults, or any other potential victims, to come forward.
In an interview with the New York Daily News, Rodriguez-Santos' mother, said her son has struggled with a drug habit, assaulted her and his grandfather and has stolen from family members.
“I never thought he would kill someone,” Fioraliza Rodriguez told the Daily News. “I was afraid of him, though, because he punched me. That’s when I told him to get out of my house.”
Fioraliza Rodriguez said her son is a native of the Dominican Republic, who moved to New York about four years ago. She said she kicked her son out of her house about three years ago.
“When I told him to leave, he came back and threatened me,” she said. “He said when I go back to Santo Domingo, he’ll get people to cut my face.”
New York City Mayor Bill de Blasio posted a message on Twitter, describing the deadly Chinatown rampage as a "senseless act of violence against the most vulnerable members of our community."
"It flies in the face of the values of our city," de Blasio said in his tweet. "We’re keeping the victims and their loved ones in our hearts today."