More than 80 evidence markers were scattered around Stockton Madison's Market on Wednesday morning, many sitting next to bullet casings. Detectives were still investigating the scene of Tuesday night's mass shooting that killed three people and injured four others. Watch report: My hands were shaking during shooting, witness says The drive-by shooting happened about 8:20 p.m. in the 700 block of North Madison Street. So far, no suspect description has been given, but Stockton police said witnesses saw shots fired from a dark-colored SUV that was going southbound on Madison Street. A 27-year-old woman died at the scene and the six other victims were taken to the hospital. A 24-year-old man and 20-year-old woman later died at the hospital, bringing the death toll to three, police said. The four men who are still hospitalized are expected to survive. A neighbor told KCRA 3's Brian Hickey she heard what sounded like more than 30 shots, and that based on the cadence of the gunfire, there was likely more than one gunman. "I was trying to get in my door and I ducked. My hands were shaking and I had the wrong keys. Then I heard a woman screaming and yelling, '911, 911'," Allison Denau said. Roxanna Thomas kept an all-night vigil at the perimeter of the investigation, hoping for any information on the victims. Thomas' granddaughter liked to hang out on the corner with her friends. "She’s just out here. I just want her to come home because that’s why I’ve been here all these hours," Thomas said. "That could be her right there." The market is a popular place for groups to gather at night, according to the Stockton Police Department. Dozens of people came together in the area Tuesday after the shooting, and additional police had to be called in to help control the crowd. Click here to sign up for KCRA 3 breaking news alerts "In my 19-year career in the city of Stockton, I have not seen seven people shot in one night," Stockton police Officer Joe Silva said. Investigators said they were having difficulty getting any information from witnesses, which could help them identify who was responsible for the shooting. "Since this is a high-crime neighborhood known for gang and narcotic activity, it’s hard for uniformed (officers) or detectives to get information at the scene just because people don’t want to be labeled as that snitch," Silva said.