The mayor of southwest suburban Willow Springs announced Wednesday morning the findings of a three-year internal investigation of the village’s police department.

Mayor Alan Nowaczyk said in a release that the internal investigation of a former Willow Springs police officer led to the firing, resignation or retirement of five officers – nearly half the department.

READ: Full statement from Willow Springs mayor

The village’s investigation of use of public funds for private business and the use of Cook County Sheriff’s funds to conduct an investigation of the mayor and others, began in 2013.

“There are several officers that were part of that phase of the investigation and currently it’s being summarized and reviewed by an outside counsel,” said Nowaczyk.

The release said one officer was fired for lying under oath, a second officer was fired for falsifying police documents, a third officer retired at the beginning of an interrogation, a fourth officer resigned after receiving notice he would be interrogated and a fifth officer resigned before the investigation was complete.

The investigation also found violations of the state gift ban act.