The two aircraft, a Swearingen SA-226TC and a Mooney M-20, collided in flight at approximately 7,000 feet MSL in the Salt Lake City Airport (SLC) radar service area over Kearns, UT. The SA-226 was approaching SLC for landing and the M-20 was conducting a local training flight when the collision occurred. There is evidence that the SA-226 initiated evasive action in the final moments before the collision. There was also an exclamatory expletive on the radio at about the time the radar targets of the two aircraft merged. The final controller saw a radar target earlier that was possibly the M-20 but did not see it at the time of the collision. The M-20 had no Mode-C transponder to help identify it on radar. The M-20 should not have been where it was without clearance. The pilot of the SA-226 had been advised of another aircraft to its left and asked to report sighting it. The M-20 approached the SA-226 from the right side. After the collision, both of the aircraft descended to an uncontrolled crash. The weather at the time of the collision was VMC with visibility of 30 miles.