MINNEAPOLIS - A 17-year-old will be charged as an adult with the murders of a 20-year-old man and a 7-month-old baby last weekend in south Minneapolis.

J'Quan LeeArthur McInnis, of Minneapolis, was charged with two counts of first-degree premeditated murder and two counts of drive-by shooting in the deaths of Gustav Christianson and Jayden Eric Redden. He is being charged as an adult, due to a previous certification as an adult for attempted first-degree robbery.

"It's not a juvenile act when you take a gun and you shoot someone in broad daylight, and then you shoot into a car and kill a kid," said Hennepin County Attorney Mike Freeman. "That's homicide, that's idiocy, and if we can prove what we've set forth in allegations, then he deserves one heck of a lot of time in the big house."

According to the criminal charges, police were dispatched to a shooting on 26th Street East and 11th Avenue South on Sunday and arrived to find Christianson lying in a nearby driveway, suffering from apparent gunshot wounds.

Soon after, Christianson was pronounced dead at the scene.

Officers spotted a vehicle near Christianson, which had its rear window shot out and quickly learned a baby sitting in a car seat inside the car had also been struck by gunfire.

Charges say the baby's father lifted the car seat out of the car with the child in it and took him to Children's Hospital, just two blocks away.

Officers responded to the hospital where the child was pronounced dead.

"This makes no sense, taking the life of another and a baby in a dispute that we're not sure of but may have been over a debt not re-paid," Freeman said.

Numerous witnesses told authorities they saw the shooter, later identified as McInnis, and gave police his description.

One witness said Christianson was sitting in the backseat of the car when the gunman started shooting. They said he then walked around to the back of the car and fired again into the back window.

Julia Johnson identified her 20-year-old brother, Gustav Christianson, as one of the victims. (Photo: Julia Johnson)

During their investigation, officers identified the suspect as McInnis. He was located and placed under arrest early Wednesday morning.

In an interview with police, McInnis admitted he had been fighting with Christianson earlier on Sunday. He said he circled the block, saw Christianson and went to confront him. He told police he had a gun and shot Christianson as he was sitting in the back of a vehicle.

He told authorities he didn't know there was a baby in the car when he started firing.