Mandan police are investigating how a counterfeit bill ended up at a bank.

Sgt. Jay Gruebele said officials at Starion Financial discovered the $20 bill. It did not change colors when marked and also did not have a water mark or a security bar, Gruebele said.

He said the bill had been left in a night deposit box and apparently had been used at a Mandan business.

Detectives are investigating the case, and it also has been sent to the U.S. Secret Service, which investigates counterfeiting, Gruebele said.

Bismarck police also have investigated several counterfeit cases recently, mostly of fake bills being passed at stores in Kirkwood Mall.

- Jenny Michael