Contractors and postal employees across the country have used government-issued Voyager credit cards to steal gas from the U.S. Postal Service, according to a series of reports by a postal watchdog.

The stolen gas was often resold, and the profits were spent buying drugs, paying for car repairs and gambling, according to the USPS inspector general.

Nearly a dozen reports on closed fuel theft investigations were obtained by the Washington Examiner in response to a Freedom of Information Act request.

In one case, two New Jersey truckers used government cards to steal more than $300,000 worth of fuel between 2006 and 2009. The Postal Service had contracted with the truckers' company.

The two resold most of the gas and used the rest for their personal vehicles, including a boat. They also used the cards to buy cigarettes and snacks, and to get cash.

Both of the New Jersey truckers were heavy gamblers and used some of their proceeds for gambling, according to witnesses quoted in the IG reports.

One of the truckers spent at least $1,000 per gambling trip. One of the thieves also called the other a "crack head."

The scam started when one of the truckers noticed his supervisor using the card to buy cigarettes and having the purchase processed as diesel fuel to conceal the transaction.

The driver arranged to pay the supervisor for use of the card, which he used to fuel a truck for his towing business on the side and to buy fuel for resale.

The truckers stole the fuel from multiple gas stations in New Jersey, including some where attendants helped process the purchases as diesel.

When agents approached one of the thieves in 2009, he confessed to the scam and helped agents monitor the other thief's fraudulent purchases, while wired with a microphone and voice recorder.

"Imagine if they got a hold of all the records of all the s--t we took? We'd be screwed," one of the drivers said in a monitored phone call.

"I'd be spending the rest [of] my retirement in jail," the other responded.

Both men were sentenced in 2011 and paid more than $335,000 in restitution, according to the IG. They were put on five years' probation each, with six to eight months of home confinement.

In a second fuel theft scheme reported by the IG, two individuals in Michigan used a Voyager card to steal $115,000 worth of fuel.

The stolen fuel was then resold at a substantial discount to a local farmer and to friends of the two thieves for their personal vehicles.

A witness told inspectors that profit from the scheme "was typically used to purchase narcotics, specifically heroin." The case is pending, according to the report.

In yet another case, a former USPS employee in Dallas used his Voyager card between 2011 and 2012 to fuel his personal vehicle, a Ford Excursion.

He was the only person in the facility who drove an Excursion, and he admitted to being the person identified in surveillance photos, but he denied stealing the fuel.

Instead, he told investigators he had no reason to steal, and that family and friends helped him when he needed money.

When investigators reminded him he had been prosecuted for theft in California in 2000, he explained that he stole merchandise he liked from his then-employer.

A customer service supervisor in Florida whose job required keeping a list of employee PINs used 22 of them to steal an estimated $1,251 worth of fuel for his personal truck in 2011 and 2012.

He told investigators he kept his purchases to 12 gallons, as much as his office's delivery vehicles hold, to avoid suspicion.