The United States Civil Rights Commission, an eight-member agency that investigates accusations of discrimination, has launched a new offensive against a most unusual target: the Justice Department.

The commission is investigating why the Justice Department dropped charges in May against three members of the New Black Panther Party for Self-Defense in a voter intimidation case that the government won.

The Justice Department has defended its actions, saying it obtained an injunction against one member while dismissing charges against the others "based on a careful assessment of the facts and the law."

But that explanation hasn't satisfied the commission or Republican lawmakers, who say the dismissal could lead to an escalation of voter intimidation.

Three members of the radical group were accused of trying to threaten voters and block poll and campaign workers by the threat of force in November 2008 -- one even brandishing what prosecutors call a deadly weapon.

The three black panthers, Minister King Samir Shabazz, Malik Zulu Shabazz and Jerry Jackson were charged in a civil complaint in the final days of the Bush administration with violating the voter rights act by using coercion, threats and intimidation. Shabazz allegedly held a nightstick or baton that prosecutors said he pointed at people and menacingly tapped it. Prosecutors also say he "supports racially motivated violence against non-blacks and Jews."

The Obama administration won the case in April but moved to dismiss the charges in May without explanation.

After Republican lawmakers pushed in the summer for an internal investigation, the Justice Department's Office of Professional Responsibility obliged, starting a probe that the department has said should conclude before it cooperates with the commission's investigation.

Rep. Frank Wolf, R-Va., announced Thursday that he had inserted language into the annual Justice funding bill that requires the OPR to provide results of its investigation -- a resolution that has been referred to the House Judiciary Committee and must be voted on within 14 legislative days.

"I regret that Congress must resort to oversight resolutions as a means to receive information about the dismissal of this case, but the Congress and the American people have a right to know why this case was not prosecuted," Wolf said in a written statement.

"Time and again over the last year, the department has stonewalled any effort to learn about the decision to dismiss the case," he continued. "I have written Attorney General (Eric) Holder on six occasions asking for an explanation for the dismissal of this case. To date, I have received no response from him."

The commission feels it is being stonewalled, too, and has filed subpoenas with the department for the information as well as to interview career attorneys that handled the case.

"They've never given a satisfactory answer," said Todd Gaziano, a member of the commission and director of the conservative Heritage Foundation's Center for Legal and Judicial Studies. "There is a heavy burden on the Justice Department to explain why those facts in the complaint do not constitute voter intimidation."

When asked about the commission's repeated requests for information, Justice Department spokeswoman Tracy Schmaler said, "We're reviewing the commission's request."

She told that the civil division at the department reviews "these types of requests in accordance with longstanding guidelines governing the disclosure of internal department information."

The commission is likely to hold a public hearing on the case early next year and could have a report out by September, Gaziano said.

The commissions sent two inquiries into the Justice Department's dismissal of the case in June and received what it called a "largely non-responsive letter" from the Justice Department in July and none of the documents requested. The commission sent another inquiry in August and September when it said it received notification from the Justice Department that it would not provide any information until its internal investigation was complete.

That prompted the commission to issue subpoenas and send its latest missive this month, a response to a Justice Department letter in November that that the commission said challenged its authority to subpoena the department or its employees.

"While your letter refers to an ongoing 'dialogue' between the Department and the Commission, it is the dearth of cooperation on the part of the Department that has resulted in the Commission's need to issue subpoenas," David Blackwood, general counsel for the commission, wrote.

"We are both mindful of the sensitivity of the subject matter involved and aware that, in response to similar requests, the department has raised various concerns and matters of privilege," Blackwood wrote. "While such considerations carry weight, cooperation with commission investigations is a mandatory statutory obligation."

"Moreoever, due to the unique investigative role of the commission -- akin to that of a congressional committee - -disclosure to the commission of the information sought it is both proper and required,' he added.

Wolf said in his written statement that the attorney general has instructed his department to ignore the subpoenas.

"The nation's chief law enforcement officer is forcing these career attorneys to choose between complying with the law and complying with the attorney general's obstruction," he said, adding that one of the attorneys has been compelled to obtain private counsel.

"The House must not turn a blind eye to the attorney general's obstruction," he said. "He has an obligation to answer the legitimate questions of the House and the Civil Rights Commission."