But the trauma of what happened in this peaceful gathering spot Jan. 15 has etched itself into the minds of the people who were there when a man, identified by police as Arthur Martunovich, came in shortly after 5 p.m. with a hammer in his hand and bludgeoned three employees to death.

The triple killing has reverberated through Sheepshead Bay, leaving workers and customers struggling to recover from the events. Some local politicians have said that Martunovich, whose family is Russian by way of Estonia, had racist motives and should be charged with hate crimes.

Dermot Shea, chief of detectives, said Wednesday that he expected Martunovich to be indicted soon. “We anticipate some kind of hate crime charges,” he said.

The Brooklyn district attorney’s office declined to say that an indictment had been handed up.

Martunovich, 34, is a construction worker who lives about 10 blocks from the restaurant, in the Brighton Beach neighborhood. He has a history of mental illness and had been hospitalized before, but had never been arrested, according to police and his friends.

“I’ve never known him as a violent person or a hateful person,” said Aleksander Krupetskiy, who has known Martunovich since high school.

That afternoon, police said, Martunovich yelled curses as he made a beeline for the restaurant manager, Thang Kheong Ng, a 61-year-old Malaysian immigrant. Unprovoked, he struck Ng over the head, spilling blood over the gleaming floor in front of the counter.

Martunovich then ran toward the buffet, filled with steaming plates of vegetables and seafood, where he swung the hammer at a part owner of the restaurant, Tsz Pun, 51, crushing his skull, police said. In the kitchen, he bludgeoned Pun’s nephew, Fufai Pun, who had worked as a chef there since he was a teenager.

Customers and co-workers ran screaming from the restaurant and onto Emmons Avenue, just off the Belt Parkway. Some sought shelter in neighboring businesses.

One of the kitchen workers, a Latino man named Miguel, told police he came face to face with Martunovich as he entered the kitchen. He screamed, “No problems! No problems!” at the construction worker and then bolted for a door.

As he ran, Miguel, who did not give his last name because he is an immigrant in the country illegally, said he heard the sickening crack of the hammer meeting bone. He recounted the scene to a detective at the restaurant Tuesday.

Fufai Pun, 34, died at the restaurant. Ng died three days later at a hospital. Tsz Pun clung to life for another week, but died Jan. 24.

Martunovich was arrested on murder charges and sent to a psychiatric ward at Bellevue Hospital Center in Manhattan. He still has not appeared before a judge, and it is unclear whether he is mentally competent to stand trial.

When he ran into the restaurant, Martunovich told a dishwasher that he wanted to hurt only Asian men, The Daily News reported.

City Councilwoman Margaret Chin, citing an unconfirmed report in The New York Post, said the attacker “saw himself as some kind of savior” after watching a film that depicted Asian men abusing Asian women. “This was a racial hate crime, plain and simple,” Chin, D-Manhattan, said at a rally outside the restaurant last week.

Councilman Mark Treyger, D-Brooklyn, called the restaurant, “the scene of a hate-crime massacre.”

Whatever his motive, Martunovich’s sanity is likely to be a factor as his case moves through the court system. Martunovich, has been undergoing psychiatric treatment at Bellevue since he was arrested Jan. 15, according to law enforcement officials. It was unclear if he has a lawyer.

Two friends and former co-workers of Martunovich said in interviews that the construction foreman had been institutionalized a few years ago.

“I spoke to his mom and she told me, a few years ago, he had a breakdown and she talked him into going for inpatient treatment at some clinic,” Krupetskiy, a longtime friend, said. “They released him and said he was completely fine. She was concerned at the time, but whoever was seeing him said he was fine and he wasn’t a danger.”

Bogdan Tselnik, a contractor on Coney Island who employed Martunovich as a carpenter up until three years ago, said he was “one of the smartest workers” at the company. But then he abruptly quit working and was institutionalized, Tselnik said.

“He went missing one day; he didn’t show up for work, and his mother had to come and pick up his tools,” he said.

Martunovich’s mother, Svetlana Chalmers, declined to answer questions about her son’s psychiatric history.

The restaurant workers did not know Martunovich. He was not a regular customer. “Nobody recognizes him,” Edwin Cheng, the interim manager, said. “Most of the people are repeat customers from the neighborhood.”

About 16 workers were at the restaurant Jan. 15. Most of them, Cheng said, had yet to return to work because they were so unnerved by the killings.

Cheng said Tsz Pun, 50, the part owner, worked in the kitchen alongside Fufai Pun, 34, who had a wife and two small children.

Tsz Pun made a living from the restaurant for two decades. He bought an apartment for his family in nearby Gravesend and helped pay to put his daughter through college at a local art school, friends said.

The other victim, Ng, had worked as a manager at the Seaport Buffet for about eight months, co-workers said. A journeyman restaurant worker, he was trying to get a green card so he could settle permanently in the United States, a friend, Lisa Lee, said.

Lee described him as a kind man who kept in close contact with his 90-year-old mother in Malaysia. “He’s a nice person, very polite,” she said.

This article originally appeared in The New York Times.