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The Utah Highway Patrol is investigating both speed and the actions of a semi-trailer rig driver in connection with fatal motorcycle crash Monday night on Interstate 84 in Morgan County.

Killed in the 6:14 p.m. accident near mile post 107 was John D. Millar, 59, of Morgan.

Troopers say Millar was westbound on his 2013 model BMW motorcycle, heading through a curve just west of Taggart, when he he lost control of his bike, plunged into the soft dirt median and collided with a cable barrier.

Millar, who was wearing a helmet, was killed on impact, UHP said.

Though excessive speed may have been a factor, troopers also were investigating whether Millar may have been cut off, or clipped by a semi making a lane change just prior to the crash.

Twitter: @remims