ST. LOUIS (AP) — St. Louis police are investigating a rash of six killings over a 24-hour period, and the city’s police chief says drugs may be at the root of most of the killings.

Four of the victims died Sunday and two more were found inside a car at 6:30 a.m. Monday.

Police Chief John Hayden says drug activity was suspected in four of the five crime scenes. Hayden says illegal drugs and gun violence “go hand-in-hand.”

Five of the victims were found inside cars, including a woman whose boyfriend was found dead in a vacant lot a short distance from the car where she was found.

Despite the latest violence, St. Louis homicides are down in 2018. The city currently has recorded 130 killings, compared to 149 at this time in 2017.