Police arrested a teenager overnight on Tuesday in the slayings of Gustav “Gutt” Christianson, and 7-month-old Jayden Redden, who died when the car they were sitting in was sprayed with bullets while parked near a south Minneapolis park last weekend.

Homicide detectives capped two days of intense investigation when they picked up the suspect, 17, who was being held Wednesday in the Juvenile Detention Center pending charges, police spokeswoman Sgt. Catherine Michal said in a news release. The Star Tribune generally doesn’t name people who haven’t been charged with a crime.

On Wednesday, prosecutors asked for an extension in making a decision of whether or not to charge the teen in the twin slayings.

“The county attorney’s office believes this young man has been certified as an adult previously, so if charges are brought, it is highly likely that he will quickly wind up in adult court,” a spokesman said in a news release.

According to state law, a juvenile who is at least 16 years old when accused of certain violent crimes can be charged as an adult if they have previously been charged as an adult with a felony.

Christianson was sitting beside Redden in the back seat of a red four-door sedan near 26th Street and 11th Avenue S., when a gunman opened fire on the car. Police say Christianson was pronounced dead at the scene, while Redden was taken to nearby Children’s Hospital, where he died.

Police are investigating whether gangs may have played a role in their deaths, but have not publicly stated a motive for the shooting.

It’s unclear what happened to the other occupants of the car.

An autopsy concluded that Christianson died of a multiple gunshot wounds, while the baby, who was strapped in a car seat, was shot in the chest.

The slayings were the city’s 27th and 28th of the year.

At an afternoon news conference, Cmdr. Eric Fors said the arrest was the result of persistence and “basic, old-fashioned shoe leather detective work” on the street.

“I’m sure that having an 8-month-old victim was something where I’m sure it probably feels, I would say, fulfilling to get some answers for the family, but the work is not done.” he said.

Fors urged anyone with information about the shooting to contact police.

“We want to know everything there is to know about this case,” he added. “Our intent is always to find out the truth. We want to know exactly what happened and there’s still a lot of work to be done.” Councilmember Alondra Cano, whose ward includes the Midtown Phillips neighborhood where the shooting occurred, said that while recent efforts to curb drug sales and human trafficking in the area had proved successful, gun violence remained stubbornly high.

“The issue of gun violence is really tough, because we have to figure out where these guns are coming from and how they’re getting into the hands of young people,” Cano said.

She said that many in the community were “still in shock” by the senselessness of the crime.

Family members told her that Christianson had been trying to put his life back together after being released from prison, said Cano, adding that nagging social and economic disparities have “created a web of challenges that make it hard for (people) to get out of” the cycle of violence.