A man was killed today in a single-vehicle crash in Hawthorne, police said. The man died at the scene of the crash at Hawthorne Boulevard and 136th Street, said Hawthorne police Lt. Gary Tomatani. Authorities were unsure when the crash occurred, but the wrecked vehicle was discovered about 4:30 a.m. by a passerby who notified police, Tomatani said. The name of the dead man, who was in his 30s, was withheld pending family notification.