SAN DIEGO, Calif. (CBS 8) - The FBI has seized a white pickup truck that sex offender John Gardner may have been driving at the time Amber Dubois went missing. Investigators are looking for DNA inside the truck that could link Amber Dubois to the accused killer. In this News 8 Investigation we learn that vehicles driven by Gardner could become key pieces of evidence.

The 2004 Chevy Silverado was repossessed from Gardner around the same time Amber Dubois went missing in February 2009. It was sold to a new owner last year at used car lot in the Wilmington neighborhood of Los Angeles.  The manager of the car lot remembers buying the truck at auction.

"It's just a standard, white Silverado pickup with four doors. We purchased it on the 9th of March of 2009 at the South Bay Auction, which is in Gardena," Ulises Galvez said.

FBI agents seized the vehicle Wednesday in Los Angeles from its current owner, an immigrant who purchased the truck last year from the Kar Connections lot in Wilmington. Agents told the current owner they needed to impound the truck for several weeks to test it for DNA.

The car lot manager says the truck was cleaned before they sold it.

"We shampoo the carpets and the seats and then wash the windows and the dash," Galvez said.

DMV records show Gardner purchased the truck in 2006. He was driving it in Nov. 2008 when he received a misdemeanor citation for possession of marijuana in Oceanside.

It was repossessed in Feb. 2009, and a short time later Gardner purchased a new vehicle.

The Heller Ford dealership in Escondido confirms Gardner paid cash for a gold, 1999 Pontiac Grand Prix in June 2009. A few months later, a Lake Elsinore girl told deputies a man who looked like Gardner tried to force her into a gold-colored Pontiac, but she got away.

Court records show Gardner has received five traffic tickets and citations since 2008, and each time the citation shows him driving a different vehicle.

In 2008 he was driving a black Hyundai four-door sedan. In 2008 and 2009 he was driving the white Chevy pickup recently seized by the FBI. In April 2009 a traffic ticket shows Gardner was driving his girlfriend's grey Ford Focus. Later in 2009, he was behind the wheel of the gold Pontiac Grand Prix. Finally, in Jan. 2010, a traffic ticket shows him driving a 2002 black Nissan Sentra with a significant amount of damage.

Records show at least two of those cars were registered to Gardner's girlfriend, 27-year-old Jariah Baker. News 8 has confirmed Baker is currently living in a residential drug and alcohol rehab house in Escondido called Serenity House. She did not respond to News 8's emails and phone messages asking for a comment.