Philadelphia auditors investigating Sheriff John D. Green's sloppy bookkeeping have raised alarming new concerns - with the city controller contending that Green and his staff created "an opportunity for fraud" by failing to adequately track $53 million handled by the Sheriff's Office.

The latest findings ratchet up the stakes in the two-month-old inquiry by Controller Alan Butkovitz, whose October demand for a complete probe of Green's financial house prompted the sheriff to delay indefinitely his planned retirement.

Green needs to be replaced, for sure. Beyond that, Mayor Nutter and City Council must seize this opportunity to enact reform.

The only way they can assure greater accountability is by eliminating the elected offices for sheriff, along with the register of wills and the city commissioners, where a top official recently was forced out for flouting the city's ban on politicking. These offices are vestiges of the past, and their functions should be reorganized and handled by appointees answerable to the mayor.

While Green remains on the scene, he serves one useful function: as a poster child for reform.

Indeed, the cost of Green's bungling continues to grow. Now the controller says the city needs to spend up to $500,000 to bring in outside professional fraud specialists to parse the sheriff's books.

Butkovitz says only so-called forensic auditors will be able to determine whether the appalling accounting mess in Green's office "has matured into an actual fraud." That's an important issue to resolve, so it's a smart move to seek expert help.

The state of Green's books apparently would make a case study of ineptitude in any accounting class. Butkovitz reports that thousands of deposits cannot be reconciled with bank statements, and thousands more were listed merely as "cash adjustments" without documentation or explanation.

After a 22-year tenure as sheriff, Green should be deeply ashamed that such audit findings likely will stand as his lasting legacy. His willingness to hang around and postpone collecting more than $377,000 under the city's controversial DROP retirement program smacks of damage control. Had the fiscal-management problems that plagued Green's office for years been of greater concern, wouldn't the sheriff have put his house in order long before now?

With the forensic audit, there's at least a chance city officials will unravel the financial mess and implement safeguards.

Taxpayers have to hope that the whole effort leads to tighter fiscal controls across city government, the possible recovery of any unaccounted revenues, and row-office reforms that assure the next sheriff won't shoot himself in the foot.