As the city nears financial collapse, owners erased at least $4.7 million in property taxes and liens this fall on more than 400 properties Wayne County appeared to sell back to them for pennies on the dollar, according to a Detroit News analysis.

That's double the number of buybacks found at 2010's Wayne County tax foreclosure auction. In many cases, no one else bids other than the former property owners, who can reclaim the properties for as little as $500 apiece.

The increase has a top aide to Mayor Dave Bing and others calling on Wayne County Treasurer Raymond Wojtowicz or the state Legislature to crack down.

"Unfortunately, some laws have loopholes, and in this case results in others exploiting matters for their personal advantage at the expense of responsible taxpayers and the city," Kirk Lewis, Bing's chief of staff, said in a statement.

"Legislative remedies must address and prevent the myriad of ways these property owners can scam the system for their personal gain."

State law allows Wojtowicz to ban owners from buying back their foreclosed properties. Macomb County officials did so this year, but Wojtowicz said it would be too hard to police in Detroit, where he sold a record 5,200 properties at October's auction.