Michigan City officers responded to a BP gas station in the 1300-block of East Michigan Boulevard just before 1:30 a.m.
Responding officers found a 20-year-old man who had been shot.
LaPorte County EMS transported the victim to Franciscan Health Hospital, where he was pronounced dead.
Investigators collected evidence from the scene and interview witnesses.
Police asked anyone with information to contact Detective Corporal Kay Pliske at (219) 874-3221, extension 1086 or via email at kpliske@emichigancity.com.
Further information was not immediately available.