CROWN POINT | The Lake County treasurer's office mailed final warnings to thousands of real estate owners who are delinquent on their property taxes.

Now they must pay up, or the auctioneer's gavel will come down July 10, 11 and 12 with their properties potentially being sold out from under them. Treasurer John Petalas said a new state law has accelerated the sale deadline, which usually was in September or October.

As of Monday, about 13,000 properties in Lake County had delinquent property taxes and were subject to the tax sale, Petalas said. That number could come down as homeowners settle up with the county between now and the sale.

The sale is an auction in which the bidding begins with the amount of taxes owed on delinquent properties. The highest bid on each parcel wins.

Last year's tax sale of more than 7,200 properties prompted interest by federal investigators into allegations that desirable properties were quietly withdrawn or steered to those with political connections.

The suspicion came in the wake of other federal investigations of manipulation of the tax collection system.

Petalas said Monday he wants to assure the public that delinquent properties will come off the tax sale only for legitimate reasons.

He said some properties were withdrawn last year when delinquent property owners flooded into his office to make their partial payments to retain their land and judges ordered properties withdrawn.

Petalas said last year's sale was his first, and he hopes the lessons learned will make the process more transparent.

"We changed the methodology we used for payment plans. We have (owners of delinquent properties) fill out an application to be on a payment plan," Petalas said. "If they have been on one before and defaulted or not paid, we do not allow them to be on it again."

He said any requests to remove delinquent properties from the sale must be documented.