Campus police are investigating thefts of cash from 20 vending machines across Kansas University’s campus, said Capt. Schuyler Bailey, a KU Public Safety spokesman. At least $1,692 was found missing Monday from food vending machines in various campus buildings.

The thefts could have occurred any time between April 19 and Monday, when vending machine workers took inventory of the machines. The machines were not damaged, Bailey said, leading police to believe the thief had a key or was able to unlock the machines by some other means. Police have not identified a suspect.