CHICAGO (CBS) — A Chicago Police officer was found dead, and his wife was in critical condition after an apparent carbon monoxide leak Tuesday night in Albany Park.

As CBS 2’s Jermont Terry reported, Chicago Police confirmed two people, including an off-duty officer, were found unresponsive in a condo in the neighborhood shortly before 8 p.m.

Sources said the officer lives in the condo and did not show up for his shift. Another officer then came to the condo and found two people unresponsive – including the male officer and a woman.

The off-duty officer, 36-year-old Xu Meng, was pronounced dead at Swedish Covenant Hospital, according to the Cook County Medical Examiner’s office.

Mayor Lori Lightfoot said the officer’s wife was still alive, but sources said she was in very critical condition. The mayor said it’s believed there was a carbon monoxide leak in the home.

“This has been a hard week for everyone, and it’s been a particularly hard week for the Chicago police department, with two police officers shot on Monday and Tuesday,” she said.

A off-duty Chicago police officer was shot in the leg when two men tried to rob him as he was getting into his vehicle early Tuesday morning in Brighton Park. The officer was rushed to Mt. Sinai Hospital in good condition. A few hours earlier, another officer was shot in the shoulder while responding to a domestic violence call in the Austin neighborhood; the bullet struck that officer’s protective vest, and he was not seriously wounded.

“These are difficult times for all of us, but we have to make sure that we don’t forget the sacrifices that our men and women who are first responders make for us every single day,” Lightfoot said.

Area Three detectives are investigating Meng’s death.