PORTLAND (AP) – A nonprofit agency that serves people with mental disabilities has filed a civil lawsuit accusing its former bookkeeper of stealing $479,000.

The Peregrine Corp., which does business as the Project for Supported Living, filed the lawsuit in Cumberland County Superior Court against 39-year-old Kristin Johnson of Windham.

According to court records, an internal review turned up evidence suggesting that Johnson had been stealing from the agency since 1999.

Johnson, who stepped down in April to take another job, was the agency’s bookkeeper since the early 1990s and was its finance director in recent years.

Portland police are investigating the case.