In the second killing of the day Saturday, a mile to the south of the one on Union, Jessica Vinson was found shot to death in the 5300 block of Vernon Avenue, police say. Paramedics pronounced her dead at the scene, in the city's Visitation Park neighborhood.

Police say they don't know who killed her. Vinson lived in the 4300 block of Maffitt Avenue.

Both homicides came in a violent weekend in St. Louis. They were among at least 18 people shot in 10 separate incidents in the city. Most of the injured suffered non-life-threatening injuries.

In most cases, police had little to go on, with victims saying they were not sure who shot them or why. Authorities believe two shootings may be drug related, and five appear connected to arguments or "personal vendettas.," a police spokesman said. None appeared to be random.

In at least one case, the shooting didn't happen where the victims said it did, and the victims stopped cooperating with investigators.

Meanwhile, three people shot themselves accidentally over the weekend in the city, police said.