A Chicago man with “anger management issues” killed four of his neighbors as they ate dinner and critically wounded another in a shooting Saturday at an apartment complex on the city’s Northwest Side, police said.

The suspect, whose identity has yet to be released, was known to the victims, Chicago police said. The man was taken into custody and a weapon was recovered at the scene.

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The shooting happened around 5:30 p.m. when the suspect, a 67-year-old retired construction worker, went into his second-floor neighbor’s apartment and killed a family of three men and a woman who were sitting at a table eating dinner, First Deputy Superintendent Anthony Riccio told the Chicago Sun-Times.

“For reasons we yet don’t know, he opened fire on all four of those individuals, killing them all,” Riccio said, adding the suspect had lived in the building for 15 years.

He then went to a unit one floor above and shot another woman, critically injuring her, police said. Chicago police initially said that five victims were dead but later clarified that one was in critical condition and undergoing surgery.

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The victims were all adults, police said. Their identities have not been released.

Riccio said neighbors described the alleged gunman as having “anger management issues.” He said the man had a history of complaints from other residents but investigators "don't know what set him off."

It was unclear how the man entered the apartments, but police said there was no forced entry.

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Chicago Mayor Lori Lightfoot called the shooting “devastating” and “unfathomable” in a statement on Twitter.

“We mourn the loss, honor the victims, and continue the hard but necessary work of keeping our neighborhoods safe, and taking guns out of the hands of those who are mentally infirm,” she said.

The Associated Press contributed to this report.