Last week, two masked robbers hit a Wells Fargo branches in Wheat Ridge, Colorado. Police believe the same pair robbed a different branch in January. They were verbally abusive toward bank staff, threatened them with handguns, and entered the vaults, taking $500,000 in the second robbery and $1 million in the first. This week, something strange happened: someone brought a third of the money back.

The question is: who, and why? An attorney brought a bag to the local outpost of the Federal Bureau of Investigation, claiming not to know what was inside. It turned out to be $500,000 from one of the robberies.

The special agent in charge told local media that it doesn’t appear that the suspects suddenly grew consciences and sent the money back. The FBI believes that someone, maybe a relative, found the money and sent it back. “I think very likely what happened is that [the robbers] stored [the cash] somewhere and possibly a family member found it and thought, ‘Oh my God, I need to bring this to the authorities so it can get back to the rightful owners.'”

Authorities believe that the same men are behind the two robberies this year, since the suspects and the robberies themselves were so similar. Wells Fargo is offering $50,000 for information leading to their arrest.

Returned $500,000 In Bank Robbery Money Adds Odd Twist [CBS Denver]

Want more consumer news? Visit our parent organization, Consumer Reports, for the latest on scams, recalls, and other consumer issues.