Detroit- On Friday a spokesman for the mayor said Bing is getting tough with speculators and owners of nuisance properties who are investing in the city because of low real estate prices but fail to maintain their properties. The mayor is enlisting collection agencies for those who owe for delinquent blight violations and utilizing an ordinance that requires owners of vacant property to register with the city, the spokesman said.

The News’ investigation found that 10 private landowners — all but two of whom live outside Detroit — own more than 5,000 city parcels. Included in the total are scores of empty lots and vacant buildings that investors bought for as little as $500 after they were foreclosed for back taxes.

The city has often struggled to hold owners of blighted land accountable. As of last year, the city Department of Administrative Hearings, or blight court, was owed nearly $41 million in fines. And buyers are flocking to the annual Wayne County tax auction. In October, the auction set a record, selling more than 4,300 properties with opening bids of $500.

Stay up to date with this story at Detroit News.com with Christine MacDonald.