A longtime emergency services worker who was killed in an unprovoked stabbing in New York City was planning to retire in a few months and spend more time with her family, the head of her union said.

Lt. Alison Russo-Elling was about six or seven months away from retirement, Vincent Variale, president of the uniformed EMS officers union, told reporters outside the hospital where Russo-Elling died of her injuries Thursday.

Police announced Friday that Peter Zisopoulos, 34, was being charged with murder and criminal possession of a weapon in the fatal stabbing of Russo-Elling, a nearly 25-year veteran of the city's fire department who was among the first responders to the World Trade Center on Sept. 11, 2001.

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Russo-Elling was on duty when she was stabbed Thursday afternoon near her station in the Astoria section of Queens, authorities said.

The 61-year-old Russo-Elling was heading to a corner store to get something to eat when Zisopoulos allegedly stabbed her multiple times, police said. She was taken to a nearby hospital, where she was pronounced dead.

Zisopoulos ran to his apartment and locked himself inside, police said. He was arrested after he was eventually talked into coming out. It wasn't clear if he had an attorney who could comment on the charges against him.

FDNY EMS Lt. Alison Russo-Elling

FDNY EMS Lt. Alison Russo-Elling. Russo-Elling, pictured here, was fatally stabbed while working. The murder was an apparently random attack. (Courtesy of FDNY via AP)

The motive for the stabbing is under investigation.

Russo-Elling joined the fire department as an EMT in March 1998 and was promoted to paramedic in 2002 before becoming a lieutenant in 2016.

A mother and grandmother, Russo-Elling lived in Huntington on Long Island and had volunteered with the local ambulance corps there, according to the Daily News.

Variale, the union president, told the New York Post that he had just spoken to Russo-Elling last week. "Alison was the sweetest, kindest person you’ve ever met," Variale said. "She was also very brave."

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Another colleague, EMS Capt. Mike Dadonna, told the Post that Russo-Elling "always greeted you with a smile. No matter what was going on, she had a smile."

Acting Fire Commissioner Laura Kavanagh, who joined Mayor Eric Adams and other officials at a news conference Thursday, said Russo-Elling was cited multiple times for bravery and life-saving work.

"And she was absolutely beloved on this job," Kavanagh said.

Adams, a former police officer whose service in uniform overlapped with Russo-Elling's, said he is very familiar with the work that EMS workers perform.

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"Every day, they do their job in a manner in which many of us don’t realize how dangerous it is," Adams said. "She was working for this city. She paid the ultimate sacrifice because of that."