A former cop who later became an executive at NASA was found guilty Thursday of first-degree murder for killing his neighbor, a Maryland National Guardsman—the culmination of years of bickering over loud music, garbage, and dog poop. Michael Hetle, 54, believed that the homeowners association and the police had not been responsive enough to his complaints about noise and trash he said were coming from 24-year-old Javon Prather’s home, according to prosecutors. So, last March, after arguing with Prather earlier in the day, Hetle, who had been involved in two (apparently justified) fatal shootings as a police officer, shot him dead. That morning, Hetle had emailed the neighborhood association with a warning that things between him and Prather could “result in tragedy,” Fairfax County prosecutor Joe Martin said in court. After nearly eight hours of deliberation, a jury found Hetle guilty. He faces a maximum of life in prison, and will be sentenced Jan. 28.