Esme Murphy

 When a couple brought their pickup truck into a Midas service center in St. Paul, little did mechanics know they would find a $157,000, highly illegal problem.

The middle-aged couple whose truck was towed in -- a 48-year-old man and 62-year-old woman from Washington state -- claimed not to have much money.

The mechanics at the Midas shop felt sorry for the two and gave them a lift to their Hastings, Minn. motel while they worked on the truck.

It didn't take long for the mechanics to discover the fuel system was clogged.

When the two suspects were told the tank needed to be replaced, they were "adamant" that the repair wasn't needed, Bailey said. Eventually, they relented but insisted that the pickup's old tank be saved.

When they removed the gas tank from the truck, they noted the tank seemed inordinately heavy. It also had new weld marks.

"It took two big guys to move that gas tank," said mechanic Ted Thompson. "For a tank without much gas in it, that is pretty unusual."

The mechanics were suspicious and anxious to see what was causing the tank's weight discrepancy. They contacted police, but opened the gas tank before they arrived to see what was inside.

The 40-gallon gas tank were two metal boxes. Needle-nosed pliers pulled out marijuana.

As authorities descended upon the scene, the Midas men cut open the boxes and revealed 150 pounds of compressed marijuana. The estimated street value of the stash is $150,000.

The couple told investigators they were driving from Yakima, Wash., to Chicago, according to Kent Bailey, acting agent in charge of the U.S. Drug Enforcement Administration's Twin Cities office.

"Their bad luck is their vehicle had some fuel problems and they ended up taking it into a Midas Shop," Bailey said.

The two suspects in the case are in jail.