Minneapolis police arrested a second suspect Tuesday in the slayings of a man and a 7-month-old boy who were gunned down as they sat in the back of a parked car in the Midtown Phillips neighborhood.

The 26-year-old man was booked into Hennepin County jail on a charge of probable cause murder pending formal charges, authorities said. As of late Wednesday afternoon, he had not been charged.

Jquan LeeArthur McInnis, 17, of Minneapolis, was charged last week with two counts each of first-degree murder and murder in a drive-by shooting after he shot at Gustav "Gutt" Christianson, apparently over a debt, prosecutors said Thursday. A grand jury will be impaneled in the next two weeks to confirm the charges, according to authorities.

Christianson was struck on Oct. 9 by multiple bullets, authorities said. He was pronounced dead at the scene.

The infant, Jayden Redden, who was strapped into a car seat, was hit in the chest, according to authorities.

Redden's father hoisted the car seat out of the car with his son in it and drove to nearby Children's Hospital, the complaint said, but the baby later died.

Karen Zamora