STAMFORD — A violent shove during an argument and a resulting fall onto a concrete sidewalk last week led to the death of a homeless man in Stamford, police said.

The victim has been identified at Leobardo Quintero, 43, police said. Officers are now looking for the person who pushed Quintero, police said.

At about 9:30 p.m. Sept. 5, police were called to Alden Street near Stillwater Avenue on a report of a man down on the sidewalk. Responding officers found a “tumultuous scene” with men and women surrounding Quintero, who was lying on the ground going in and out of consciousness after having hit his head on the sidewalk, according to a police statement.

Quintero was rushed to the Stamford Hospital emergency room, but by the next afternoon he was listed as brain dead in hospital records, said. Sgt. Sean Boeger, who is heading up the investigation. Early Tuesday, Quintero was taken off life support and died.

The Office of the Chief Medical Examiner ruled that Quintero died of a blunt impact injury to the head, which caused a subdural hematoma. The manner of death was homicide.

“Our thoughts and prayers are with the victim’s family,” Capt. Richard Conklin said.

Quintero’s death marks the third homicide for the year in Stamford, Lt. Michael Noto said.

On March 30, Stephon Walthrust of Queens was shot and killed in Stamford’s South End. On May 22, 54-year-old Enrique Gutama was stabbed to death with an open pair of scissors during an argument. Arrests have been made in both cases.

Boeger said investigators determined that Quintero was involved in a heated argument with several people before he was pushed to the ground. A suspect has been identified, Boeger said, but he declined to elaborate.

Twin sisters Emily and Linda Soto say they will miss Quintero.

“He was my best friend. He would tell me everything, everything,” said Emily Soto, 28. She said Quintero did not have a stable place to stay and had a minor drinking problem but rarely, if ever, imbibed during the day.

“I think it was messed up, when they just pushed him,” Soto said Wednesday, standing near a memorial of flowers and candles on Alden Street only feet from where Quintero fell, shattering his skull. Soto said Quintero was not married and had no children, but he is survived by two brothers who live in Michigan.

“He was a lovable person,” her sister added. “Everybody loved him. He always put a smile on everyone’s face. He was like a brother.”

Linda Soto said life without Quintero will be different.

“It’s very hard. I still can’t accept that he’s gone. I want him to still be here. I want him to come around the corner like he used to and make everybody laugh. That was his personality,” Soto said. “You would never see him mad. If he had his last dollar, he’d give it to someone else.”

During his time in Stamford, Quintero had several run-ins with the police. He also drifted from address to address.

Police records indicate Quintero has been in Stamford since at least March 2005, when police listed him as a witness to an assault. At the time, he told police he lived on Cold Spring Road. But when he was the complainant for a disorderly conduct call at Curley’s Diner in 2009, he was living on Smith Street.

In 2015, when he was charged with creating a public disturbance, his listed residence was on Hazel Street.

In 2017, police said he tried to pull a stop sign out of the ground on West Broad Street. At that time he was listed as homeless.

In 2018, he was the victim of an assault, and in January 2019, he was charged with breach of peace for allegedly throwing birthday cake on a man in a wheelchair. Quintero at the time told police he had no stable address.

Heavy alcohol use was a reported factor in several of the police cases, and Boeger said drinking appears to have been involved in the latest incident. Boeger said investigators do not know what the argument was about that lead to the shove.

Anyone with information on the case is asked to contact Sgt. Sean Boeger at 203-977-4421