On Friday, St. Louis Police allege that a house explosion killed four people, three of them teenagers, attempting to make fireworks. Now, two men have been charged with murder in connection to the event, reports the St. Louis Post-Dispatch. According to prosecutors, Terrell Cooks and Seneca Mahan supplied the victims with the materials to make the explosive powder that police believe caused the fatal blast. The two men are charged with three counts of second-degree murder and numerous less crimes in charging documents that allege Cooks was one of the “leaders of the manufacturing process,” and admitted that he and Mahan made explosive devices meant to produce a significant bang and flash. Cooks said that he instructed the victims—aged 16, 17, 18, and 21—on how to load the explosive powder into canisters. “If you buy 50 pounds of any explosive, you have just created a bomb,” the fire chief said.