A gunman opened fire inside a Philadelphia Kmart Tuesday morning, critically injuring a store manager, and police were going door-to-door in their hunt for the shooter.

Officer Christine O'Brien said the shooting happened about 9:30 a.m. Tuesday during an apparent domestic dispute in the store in the 8800 block of Frankford Avenue in Torresdale.

The 35-year-old victim, described as a black male, was intervening in an argument between a co-worker and her ex-boyfriend when he was shot three times, once in the head, arm and chest, O'Brien said.

Police have fanned out around the store in search of the gunman, identified as 30-year-old Daryl Anthony Birch and considered armed and extremely dangerous. They were going door-to-door with SWAT teams in search of Birch.

The wounded man was initially in critical condition at Frankford-Torresdale Hospital but was listed as stable later Tuesday. His name has not been released.

Birch is described as a black male about 5'10", wearing a black hat and black hooded sweatshirt. He is reportedly driving a gold Nissan with a black door and a red hood, according to MyFOXPhilly.com.

The victim was shot after Birch and an ex-girlfriend began arguing inside the store and Birch allegedly pulled out a gun and threatened her.

She fled into a stock room and Birch allegedly fired several shots, hitting a store manager.

Two elementary schools in the area were locked down after the shooting.

Patrol cars parked out front and officers turned away customers at the door.

A Chicago-based Kmart spokeswoman declined to comment.

Click here for more on this story from MyFOXPhilly.com.

The Associated Press contributed to this report.