MADISON, Wis. (AP) — A Milwaukee man shot and killed five of his family members, including four teenagers, before calling police and saying “I just massacred my whole family,” according to a criminal complaint filed Thursday.

The Milwaukee County District Attorney's office charged Christoper Stokes, 43, with five counts of first-degree homicide for the Monday attack. Each count carries a potential sentence of life in prison. He was also charged with being a felon in possession of a firearm.

The complaint said Stokes identified himself on the 911 call and said “the gun is still upstairs with the bodies.” Stokes told the dispatcher he was sitting outside on the steps. He called 911 a second time and again confessed to killing his family with a shotgun, the complaint said.

When police arrived at the house, Stokes was sitting on the steps. When an officer asked Stokes if he had heard any shots, he responded, “Yeah, I didn’t hear them, I did them," according to the complaint.

Police discovered a camouflaged 12-gauge shotgun in one of the bedrooms with 12 spent shotgun shells throughout the house.

The victims were ages 14, 16, 17, 19 and 41. Milwaukee Mayor Tom Barrett said on Monday that an infant was found alive in the house.

No attorney was listed for Stokes in online court records.

Stokes pleaded guilty in 2007 to felony battery, felony bail jumping and felony intimidation of a witness. He was sentenced to four and a half years in prison, prohibited from possessing firearms and ordered to complete a batterers’ intervention course.

Five years later, in 2012, he pleaded guilty to misdemeanor battery with a domestic abuse modifier and drew 18 months in prison with another gun ban. In 2017, he pleaded guilty to misdemeanor disorderly conduct and was sentenced to a month in jail with work-release privileges.

Stokes was also convicted in 2002 of misdemeanor battery. He was sentenced to probation, ordered to attend domestic abuse counseling and prohibited from possessing firearms.

The attack was the second mass shooting in Milwaukee this year. Molson Coors brewery worker Anthony Ferrill gunned down five co-workers on Feb. 26 before turning his gun on himself. His motive remains unknown.