The head of a federal inquiry into the firings of eight U.S. attorneys claims the Justice Department has impeded his investigation.

In a letter sent to Attorney General Michael Mukasey last week, Office of Special Counsel chief Scott J. Bloch said the department has thrown up roadblocks that hindered his investigation.

Specifically, Bloch said, the department's inspector general and office of legal counsel asked him to step aside until internal investigations are finished.

But that could take months, Bloch wrote, effectively pushing his agency's role "into the very last months of the administration when there is little hope of any corrective measures or discipline possible."

The Office of Special Counsel is a small, independent federal agency charged with protecting the rights of federal workers and ensuring that government whistle-blowers aren't subject to reprisal.

Bloch also complained that his attempts to meet with White House Counsel Fred Fielding to discuss the investigation have been rebuffed. The White House did not immediately return phone and e-mail messages seeking comment Tuesday.

The firings of eight U.S. attorneys provoked a backlash on Capitol Hill last year, where lawmakers questioned whether the moves were politically motivated. That undermined the position of Alberto Gonzales, who wound up resigning as attorney general. (A ninth U.S. attorney, Todd Graves in Missouri, said he was forced out).

Bloch's letter was first reported Tuesday by the Los Angeles Times and MinnPost.com, an online Minnesota news site.

Bloch also complains about the investigation into the performance of Rachel Paulose, who recently stepped down as U.S. attorney for Minnesota amid complaints about her management style, to take a job with the department's Office of Legal Policy.

He referenced a letter he had sent to Mukasey on Nov. 19 -- the same day that Paulose announced her resignation -- in which Bloch concluded that there is a "substantial likelihood that U.S. Attorney Paulose has grossly mismanaged" the U.S. attorney's office "and has engaged in abuses of her authority" in that job.

Bloch's agency had referred allegations about Paulose to the inspector general's office, but the office told him by telephone in October that it had "asked around" and wasn't planning to do anything.

Then in December, according to Bloch, Associate Deputy Attorney General David Margolis wrote to him, demanding a retraction from Bloch's "substantial likelihood" finding. That finding was based on allegations made by John Marti, who resigned from his management post as first assistant U.S. Attorney under Paulose.

Bloch bluntly asks Mukasey: "Are you requesting that I report to the president that you refuse to investigate disclosures of wrongdoing made by a career federal prosecutor, an employee of your agency?"

The department's behavior, Bloch claims, "reveals a disturbing pattern of disregard for the authority of my office."

In an e-mail, Justice Department spokesman Peter Carr said, "We are reviewing the letter and will respond to Mr. Bloch as appropriate."

Mukasey is scheduled to testify before the Senate Judiciary Committee on Wednesday, his first oversight hearing since becoming attorney general.

Bloch himself is under federal investigation for alleged misconduct.

In 2005, a group of current and former Special Counsel employees filed a complaint against him, claiming he retaliated against those who disagreed with his policies through intimidation and involuntary transfers. The Office of Personnel Management is investigating.