A Highway Patrol trooper had no right to stop Jose Francisco Arroyo two years ago while driving along I-15 near Nephi, but Arroyo still must stand trial in connection with cocaine found in his truck, appeals court judges have decided.

In a decision released Wednesday, three Utah Court of Appeals judges said Trooper Paul Mangelson violated Arroyo's constitutional rights when he stopped Arroyo's camper truck. But that violation was negated when Arroyo agreed to let Mangel-son search his truck, they said.Mangleson had completed his shift and was on his way home Sept. 15, 1987, when he noticed the truck following closely behind another car. He pulled along side the truck and saw that it was following the car in front by three to eight car lengths at 50 mph and that the occupants were Hispanic..

Mangleson stopped the camper and cited Arroyo for following too closely and for driving with an expired license. He then asked Arroyo if he could search his truck.

Arroyo agreed to the search, and Mangleson found a kilogram of cocaine inside the passenger door panel. Mangleson then cited Arroyo for possessing a controlled substance with intent to distribute.

In the trial, 4th District Judge Ray M. Harding refused to allow the cocaine as evidence against Arroyo, ruling the trooper had no legal right to stop him. The state appealed.

The appeals court decision, written by Judge Judith M. Billings, agreed with Harding's decision that the traffic stop was illegal.

"Trooper Mangleson did not stop Arroyo until he had pulled alongside the truck and observed that the occupants were Hispanic, having already noted that Arroyo was driving a truck with out-of-state license plates," Billings wrote. "We are persuaded that a reasonable officer would not have stopped Arroyo and cited him for following too closely except for some unarticulated suspicion of more serious criminal activity."

However, the court noted that during the original hearing Arroyo and his attorney never contended the state's argument that he voluntarily allowed his truck to be searched.

Arroyo's consent to the search "purged the taint" of the illegal traffic stop, according to the decision.

Arroyo will have to stand trial in 4th District Court.