Tests on bullet fragments and casings have determined that the same firearm was used in a string of shootings across several southeastern Michigan counties.
Police in Wixom say Friday that evidence from Oakland, Livingston and Ingham counties is related.
Shots have been fired on at least 22 cars since Oct. 16. Most of the shootings involved cars near Interstate 96, and 10 of them were in Wixom, northwest of Detroit.
No injuries have been reported and there have been no shooting incidents reported since Oct. 18.
The analysis of the evidence from the shootings was moved quickly to help in the investigation. Authorities say they have received more than 400 tips in the case.
Based on reports, authorities said the gunman appears to be a man in his 30s.