SAN FRANCISCO (CBS/AP) — San Francisco prosecutors won’t file criminal charges in the case of a property management firm accused of laundering thousands of dollars in contributions to Mayor Ed Lee’s election campaign last year.

Prosecutors have said there was insufficient evidence to support charges.

READ MORE: 6 Arrested After 2 Sideshows In Vallejo

The case had centered around $4,500 in contributions to Lee’s campaign from employees and associates of Archway Property Services. Lee’s campaign returned the money after the newspaper asked about the donations and campaign officials notified prosecutors.

The newspaper said it had an email from Archway’s managing director who told donors to write a check at a fundraiser for Lee and they would be reimbursed for their contribution.

READ MORE: Plan For Urban Village At San Jose's New BART Station Raises Concerns With Local Businesses

State law prohibits being reimbursed for a contribution.

(Copyright 2012 by CBS San Francisco. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.)

MORE NEWS: Passenger Jet Narrowly Missed Truckee Homes When It Crashed