A cemetery groundskeeper discovered that about 30 headstones had been overturned between Wednesday afternoon and about 7:45 a.m. Thursday.
Two men worked through the day Thursday to resurrect the stones atop disrupted gravesites.
According to the Greenwood Cemetery office manager, while not common, it has happened in the past. Between 2008 and 2009, 74 stones had been tipped over.
The portion of Greenwood Cemetery disturbed this week was in an older section north of where Civil War soldiers are buried.
Bemidji police Capt. Mark Marcotte said criminal charges associated with the crime would likely be damage to property, vandalism or possibly desecration of a grave. However, a police report had not yet been filed Thursday afternoon.