(CNN)A 2-year-old was killed and three others -- including a 9-year-old -- were wounded in two separate shootings on freeways in Detroit Thursday night, according to Michigan State Police.
2-year-old killed, 3 others injured in two shootings on Detroit freeways
The first shooting occurred on Interstate 75 near Seven Mile Road around 9:45 p.m. local time, MSP's Detroit division said on Twitter, when someone opened fire from a light colored four-door car that had pulled up next to the victims' vehicle.
"The victim driver pulled over at McNichols (Road) and noticed both of their children were shot," the state police said.
The 2-year-old boy was taken to a local hospital where he was pronounced dead, police said. The 9-year-old boy is in serious condition at the hospital.
Police have made arrests in the shooting but will not publicly identify the suspects until they're arraigned, MSP spokesman Michael A. Shaw told CNN on Saturday.
The second shooting took place approximately 10 miles away, about an hour later, just after 11 p.m., state police said, along Michigan 39 southbound near Plymouth Road.
"A driver of a passenger car was driving south on the Southfield Fwy near Schoolcraft, city of Detroit when a unknown vehicle pulled alongside and began shooting," state police tweeted.
In this incident, the victim driver suffered a gunshot wound through the shoulder, police said, while a passenger in the rear seat sustained a gunshot wound in the knee. Both were taken to a local hospital.
A motive has not been determined in either incident and the investigations remain ongoing. Police are asking any witnesses to the shootings to contact investigators.
The two shootings are not connected, Shaw said.