MILWAUKEE (CBS 58) -- A crash turned into a shooting on the city's north side, leaving investigators stumped and needing help. 

It was Jan. 31, around 6 p.m. Milwaukee police said a 27-year-old man was driving eastbound on Villard Avenue. When he got to Green Bay Road, another driver hit him. 

Both got out of their cars and started arguing. That's when, police said, a passenger inside the second vehicle started shooting. The victim was hit in the arm and will be okay, but police have no video, casings, or suspects. 

If you know anything about this incident, call Milwaukee Crime Stoppers at 414-224-TIPS. You can also submit a tip to the P3 app in the app store. Your identity is always anonymous and you could get a reward if your tip leads to an arrest.