Sunday afternoon in The Merrillville area, State Trooper Alissa Partyka was dispatched to a two-vehicle property damage crash on I-65 southbound at the 255 mile-marker.  Investigation at the scene showed that a Ford Mustang rear-ended a Ford F150 truck at a high rate of speed.  The Mustang sustained substantial front-end damage.  Several witnesses to the crash stopped or called to report the driving behavior of the Mustang prior to the crash.  Those witnesses all stated that the Mustang had been racing a green sport bike prior to the crash.  Both vehicles were reportedly passing on the shoulders, weaving in and out of traffic and driving at speeds estimated to be over 100 m.p.h.  The driver of the Mustang, 25 year old Tyler Rimkus, from Lake Station, was cited for participating in a speed contest.  Witnesses also stated that after the crash, the motorcycle briefly pulled over to the right shoulder and then left.  Further investigation resulted in troopers locating the motorcycle at an address in Portage.  Troopers spoke to the owner and determined that this was the motorcycle involved.  The motorcyclist, Zachary Alexander, was also cited for Participating in Speed Contest.