Law enforcement authorities are looking for what they believe is a hit-and-run driver who killed a mentally ill, homeless man in Milwaukee. The body of 63-year-old Roderick Greengrass was found in an alley early Sunday morning. Investigators say his injuries were consistent with being hit by a vehicle. A Silver Alert had been issued for Greengrass after he went missing from Aurora West Allis Medical Center. People living nearby had reported a man going through garbage in that alley and a black pickup was seen driving through the alley shortly before the body was found. Greengrass suffered from delusions and had been staying at the hospital until his family could arrange a guardianship.