Bloomberg reports that one of the longest running investigations ever conducted (or, perhaps, the longest) by the CFTC (Commodities Futures Trading Commission) should finally come to an end in the months ahead as the probe into manipulation in the silver market is apparently winding down, verdict uncertain.

A four-year probe of potential price manipulation in the silver market may be completed as early as September, according to Bart Chilton, a member of the U.S. Commodity Futures Trading Commission.

“I am hopeful and expect the silver investigation to conclude in the not-too-distant future, hopefully in September or October,” Chilton, a 52-year-old Democrat, said in an e- mail. “It has already taken way too long.”

The enforcement division of the Washington-based agency, the main U.S. overseer of derivatives markets, began pursuing allegations of manipulation in the silver market in September 2008. Investigators have analyzed more than 100,000 documents and interviewed dozens of witnesses, the CFTC said in a November 2011 statement.

Chilton, who didn’t say whether the probe has uncovered evidence of manipulation, said previously that there had been “repeated attempts” to influence prices.

“There have been fraudulent efforts to persuade and deviously control that price,” he said at an October 2010 hearing in Washington. “Any such violation of the law in this regard should be prosecuted.”

Though the Dodd-Frank Act has lowered the bar for prosecuting market manipulation, don’t be surprised if the result this time around is the same as it was back in 2008 when the group found no evidence of big banks such as JP Morgan exerting an undue influence on the silver price in prior years.

As we’ve learned recently, just about every other market is manipulated in some way, but not gold and silver.