Lose $10,000 on a MAX train? The Beaverton Police Bureau has your loot.

On May 9, maintenance crews checking sand boxes under the train, which are used to give wheels traction, found a stack of bills under a seat cushion.

"I was shocked to find it was the real deal, a wad of cash," the worker who found the money said, according to a blog by TriMet. He added that the crew that found the money held the stacks up to the train's security camera to document what they found.

"It didn't look like it was that much, but when we were counting it out it was like, 'Oh wow' that's really $10,000," the team's supervisor said. "It was mind-blowing."

The money was found while the train was in Beaverton, meaning police in that jurisdiction currently hold the cash.

Officer Jeremy Shaw, public information officer for the Beaverton Police Department, says the agency "has not had any luck," identifying where the money came from.

"We're kind of hoping the release from TriMet will spur whoever owns it to come forward and identify themselves," Shaw says. "[But] you don't just misplace $10,000 in the seat of a MAX train. The possibility exists that it has something to do with criminal activity.

"If that's the case," he adds, "I highly doubt anyone will step forward."

If the money is left unclaimed, Shaw says it will be absorbed into Beaverton's general funds as abandoned property—meaning, the "finders keepers" rule will not apply to TriMet workers.

"Integrity first," the team supervisor said, "service before self and excellence in all we do. These guys really exemplify that."