(Gresham, OR)  --  An investigation is ongoing into a drive-by shooting that injured seven people attending a vigil in Gresham.  Police say they're still searching for suspects in connection to the shooting late Monday night near Southeast 174th Avenue and Stark Street.  Investigators believe members of the crowd returned gunfire.  The group was holding a vigil to remember 22-year-old Alejandro Barajas, who was shot and killed at that same location Sunday night.  Police describe the suspect vehicle as a dark-colored SUV.