Police said an armed kidnapping suspect was still at large late Friday after he abducted an 18-year-old in South Anchorage and forced the teenager to drive his own pickup south of the city.

Using a hidden spare key, the teen escaped when the man told him stop driving, got out of the red Chevrolet pickup and walked to the side of the road to relieve himself, police said. Alaska State Troopers and Anchorage police officers on a manhunt for the suspect closed the Seward Highway at Turnagain Pass for more than two hours Friday afternoon.

It started in the 8100 block of Lake Otis Parkway around noon. The teenager saw the suspect, described as a white man in his 40s, "rummaging" through things in the victim's grandmother's backyard, said police spokesman Lt. Dave Parker.

"The fella produced a handgun, pointed it at him and forced him into his own vehicle," Parker said. "The suspect forced him to drive out of town. And when they got to Turnagain Pass, he had to answer nature's call."

They stopped alongside the roadway, and the suspect got out of the 2000 red Chevrolet pickup, taking the key and the gun with him, Parker said. The teenager stayed in the pickup, the police spokesman said.

"The victim had hidden a key in the vehicle. So he drove off," Parker said.

The victim sent a text message to a family member, who called 911. After troopers talked to the teen, the manhunt was on, Parker said.

"That's why they closed down the highway. There's a guy out there with a gun."

Police and troopers flooded into the Turnagain Pass area, looking for the suspect with a helicopter, search dogs and officers on the ground, Parker said. In a written statement announcing the highway's reopening about 3:30 p.m., a troopers spokeswoman advised motorists against picking up hitchhikers. Troopers called off the search at about 4:30, but police continued to investigate.

The suspect was described as a roughly 40-year-old white man with a shaved head standing about 6 feet tall. He has a black and red tattoo on his left shoulder and was last seen wearing a black tank top, black pants and was carrying a blue and white windbreaker, troopers said.

Parker said there did not appear to be any previous connection between the suspect and the victim.

Motorists in the area described major traffic backups in both directions north and south of Turnagain Pass during the hours-long closure.

Gene Wilson, a driver for Alaska Cruise Connections trying to get from Anchorage to Seward, said he stopped his motorcoach loaded with 13 passengers in Portage at the Alaska Wildlife Conservation Center. The out-of-state and out-of-country visitors were trying to make it to a cruise ship on time, Wilson said during the closure.

"There's no point in going farther. At least here my clients have food and water and facilities," Wilson said. "I'm not going to go up into that mess."

Contact Casey Grove at casey.grove@adn.com or 907-257-4589.