Even before the elderly night-shift deli worker on the Upper East Side was shot and killed by a robber wearing a hazmat suit, a close friend of his had expressed concern for his safety.

The 67-year-old victim, who police believe was targeted in a series of robberies, had already experienced a robbery scare the previous year, but he was assisted by his friend who stayed with him in the store to ensure that he wasn’t alone.

“I said, ‘Mike. I don’t think you should be here by yourself,’” Helen Rambert, 67, recalled of a conversation she had with the victim.

Around 11:20 p.m. on Friday, the gunman killed him while he was working at Daona Deli and Grocery located on E. 81st St. and Third Ave.

The police have not yet disclosed the full name of the victim. However, neighbors and friends have created a small memorial outside the deli and have identified him as “Michael.”

Rambert recounted an incident from last year in which she found her friend working at the store at 3 a.m. and feeling terrified that a customer inside might rob him. As a result, she stayed in the deli until the man left.

“Once the guy walked out the store, he hugged me so tight. He squeezed me. He said, ‘Thank you. Thank you so much … I think the guy was trying to rob me,’” she told the Daily News. “Ever since then, we were like two peas in the pod.”

Having lived in the neighborhood for 15 years and often going out at night, Rambert would frequently encounter Michael during her early-morning shopping trips.

“He’s the night worker. He has been very close to me and I’ve been very close to him. We joke around and stuff like that,” she said. “Sometimes late night — 1, 2 o’clock in the morning — I would come and get my items and he’s there.”

She had been worried about his safety during the night shift for as long as a decade ago.

“I asked him. I said, ‘Mike, why are you working here late night by yourself?’”

His response was, “Oh, it’s OK. I’ll be OK,” she recalled.

According to police sources, the victim was behind the counter on Friday night when a robber wearing a mask and a white hazmat suit entered the store and demanded that a customer get down on the floor and empty his pockets.

After the customer complied, the gunman turned his attention to Michael and struck him in the head with the butt of his gun.

The robber then walked towards the back of the store, and the customer fled after hearing a gunshot. The bullet went through the victim’s left hand and then hit his head.

Another friend, Alan Mandel, 71, had seen Michael about an hour prior to the incident when he had gone to get a cup of coffee.

“I know Mike was on duty. And no one was in the store,” Mandel said. “We had our greetings. ‘Medium?’ ‘ Yeah.’ ‘How many sugar?’ ‘Three’ … And we just had a little chat.”

Mandel described Michael as vigilant yet kind, adding that he would often allow homeless people to seek shelter from the cold inside the deli.

“Even if they don’t admit it, everyone is worried and looks over their shoulder at night,” he said of the neighborhood.

Police reported that about half an hour later, an armed man wearing a Tyvek-style hazmat suit robbed YaYa Deli in the Bronx, located on Melrose Ave. and E. 160th St. The distance between the two crime scenes is approximately 5 miles.

The gunman “calmly” demanded all the money in the register, “no less than $1,500,” and five cartons of cigarettes, the worker recalled. “As he pointed the gun at me, a customer walked in and immediately ran out.”

“In the moment I just felt surprised, like shocked something like that would happen in this neighborhood. It was my first time getting robbed,” he said. “When you see a mask and a hazmat suit nowadays, it looks normal with all those COVID things.”