A retired New York City correction officer was shot and killed by Suffolk County cops in a gory scene in front of his Long Island home Friday after he allegedly charged at officers with a knife, according to police and law enforcement sources.

Brentwood resident Bruce Boyd, 54, was bleeding from self-inflicted stab wounds and allegedly threatening his wife before police entered the house around 12:30 p.m. in response to a welfare check, authorities and sources said.

Officers quickly pulled back when they saw he was armed, but Boyd allegedly rushed at the cops and ignored their commands to drop the weapon, police said.

At least one officer shot Boyd, who was then rushed to South Shore University Hospital in Bay Shore, where he was pronounced dead, the department said.

Boyd was “holding a knife drenched in blood from what appears to be at least two self-inflicted stab wounds,” Suffolk Police Commissioner Kevin Catalina said during a news conference, according to Newsday.

Officers responded to the scene on Wurz Street after a family member called for help, and Boyd’s wife let them inside, according to police.

Boyd worked as a training officer for the Department of Corrections’ emergency service unit, sources told The Post.

He retired from the job about five years ago.

A source who worked with him told The Post people who knew Boyd are “in shock.”

“He was a great guy. A great correction officer,” the source said. “A lot of the younger officers looked up to him.”

While police had previously responded to “emotionally disturbed calls” tied to Boyd, he did not have a criminal history, Catalina said, per Newsday.

Boyd served the Big Apple agency with “pride and honor, the NYC DOC Hispanic Society said in a social media post.

“As member of the department’s Emergency Service Unit as a trainer Officer Boyd supported and guided our uniformed staff in some crucial training and knowledge,” the organization wrote.

“Our thoughts and prayers are with his family and loved ones.”