A man was arrested in a road-rage incident in Salt Lake City early Friday morning after he unknowingly targeted an off-duty police officer in an unmarked car.

Just after 1:30 a.m. a Salt Lake police sergeant was driving home near 500 South and 300 West when a car in front of him changed lanes quickly and cut him off, said Salt Lake police detective Roger Williams. The officer honked his horn at the driver.

The driver then slowed down and pulled up alongside the officer.

"He said, 'Watch it or I will shoot you,"' Williams said.

At that point, the officer slowed his car down to move away from the driver. The other driver, however, slowed his car again as well to keep parallel with the officer and "made a motion as if he was accessing a weapon from the floor board," he said.

The officer followed the other driver onto I-15 and called for backup. Near 4500 South, a massive showing of law enforcement from the gang unit as well as officers from other agencies pulled the vehicle over.

Santiago Martinez, 25, was arrested and booked into the Salt Lake County Jail for investigation of possession of cocaine, a second-degree felony, and aggravated assault, a third-degree felony. He was being held Friday on no bail.