Police in Maryland say they have "no idea" why a 27-year-old man killed four people, including his parents, before taking his own life Sunday. Investigators say Joshua Green's rampage started at his parents' home in Baldwin, where the bodies of 58-year-old Douglas Green and 62-year-old Olivia Green were found, the Baltimore Sun reports. Police say that after Green killed his parents, he went to a Royal Farms convenience store in Essex, 18 miles away. Green used his vehicle to block a car in the parking lot before shooting its driver, 62-year-old Alpha Smith, police say. Inside the store, he killed customer Silvesta Daye Jr., 43, and shot and seriously injured a 22-year-old employee, police say.
Investigators say Green then went to his nearby apartment and set it on fire, the New York Times reports. He was found dead from a self-inflicted gunshot wound in the building's parking lot. Police found the bodies of his parents in their home's garage when they went to notify them of their son's death. "As to why this occurred, we have no idea yet," Baltimore County Police Col. Andre Davis said Monday, per the AP. "Our homicide detectives are tirelessly investigating a motive, but it appears that the shooter acted alone." Davis said the gun Greene used was legally purchased last year. (Read more Maryland stories.)