Youngstown police are investigating a homicide tonight on the city's north side. Police found 38-year-old Sammuel Buxton shot in the back in the back yard of a home off Halleck Street around 3 this afternoon. Witnesses say they heard 4 shots fired. They saw a white male with a black mustache took off in an older white car after the incident. Witnesses also saw a newer silver Grand Am or Grand Pris take off. Police say two black males in their 20's were also seen running from the scene. Buxton was pronounced dead at Saint Elizabeth's hospital.