Gallup, N.M. ? A 17-year-old boy was killed early Thursday after he jumped from a moving semitrailer on Interstate 40, a McKinley County Sheriff’s Department spokesman said.

Philip Lawson, of Wichita, Kan., argued with his father, Christopher Lawson, just before he jumped out about 10 miles east of Gallup, Lt. Roger Mace said.

Christopher Lawson told deputies that his son also was suicidal, Mace said.

Philip Lawson was pronounced dead at the scene.