A growing number of Republican lawmakers are pressing Attorney General Eric H. Holder Jr. to appoint an independent counsel to investigate the collapse of MF Global and the firm’s misuse of customer money.
In a letter to Mr. Holder, more than 20 House Republicans are calling for an outside prosecutor to handle the high-profile case. With an outsider leading the charge, the lawmakers say, the investigation will be free of political favoritism for MF Global executives with ties to the Democratic Party.
Such a move would strip authority from regulators, federal prosecutors and the Federal Bureau of Investigation, all of which are examining how an estimated $1.6 billion in customer money disappeared from the firm before its demise on Oct. 31.
The Republican lawmakers, led by Michael G. Grimm, a Republican from New York, plan to stage a press conference in Washington on Wednesday to formally request an independent prosecutor. MF Global customers are also expected to attend the event.
The request comes as lawmakers and customers grow impatient with the progress of the federal investigation, which has yet to yield any charges or actions. Some investigators have expressed doubt that they will have enough evidence to mount a criminal prosecution.
It is unclear whether the plea for an independent prosecutor will cause criminal authorities to change course. A Justice Department spokeswoman declined to comment.
Some investigators have dismissed the effort as a partisan swipe from Republican lawmakers. The Republicans directed their concerns, in part, at Jon S. Corzine, the former head of MF Global. Mr. Corzine is a prominent member of the Democratic Party, having served as a United States senator and New Jersey governor.
At times, partisan spats have emerged at public hearings into the firm’s collapse. In March, lawmakers on the House Financial Services Committee sparred after some Republican members accused the Department of Justice of failing to fully investigate the matter. The accusation suggested that Mr. Corzine, who has raised money for President Obama’s re-election, was given a free pass.
The letter to Mr. Holder, signed by Representative Michele Bachmann of Minnesota, among others, echoed these concerns.
“Clearly it would not strain credulity for the American people to perceive a conflict of interest when an individual raises large sums of money for the president’s re-election campaign,” the lawmakers wrote.
But in the letter, the lawmakers also acknowledge having no proof that prosecutors were letting Mr. Corzine off the hook.
“We wish to be clear that, at this time, we have no direct evidence that either your office or the Department of Justice is providing special treatment in this case,” according to the letter to be sent to Mr. Holder.
The main regulator investigating the case, the Commodity Futures Trading Commission, has selected a Republican to oversee the MF Global matter. The Republican, Commissioner Jill Sommers, took over for the agency’s chairman, Gary Gensler, who stepped aside after questions were raised about his past ties to Mr. Corzine, his former colleague at Goldman Sachs.
A spokesman for Mr. Corzine declined to comment. Mr. Corzine has not been accused of any wrongdoing.
Mr. Grimm, meanwhile, faces questions of his own. A military veteran and former F.B.I. agent, he is under scrutiny for his business practices and his ties to a fund-raiser under investigation for embezzling money. Mr. Grimm has not been accused on any wrongdoing.
