Restricted access to critical documents has impeded investigations into misconduct at federal agencies ranging from sexual assaults of Peace Corps volunteers to the botched gun-smuggling Operation Fast and Furious, internal watchdogs told the House Committee on Oversight and Government Reform Wednesday.

Inspectors general from three agencies also said they often have trouble fully pursuing fraud or misconduct investigations because they have no power to compel statements from anyone besides federal workers.

That means a federal employee under investigation can simply retire or quit to avoid an interrogation by the IG.

“To conduct effective oversight, an OIG (Office of Inspector General) must have complete and timely access to all records in the agency's possession,” Michael Horowitz, inspector general for the Justice Department, told the committee.

“Restricting or delaying an OIG’s access to documents may lead to incomplete, inaccurate or significantly delayed findings or recommendations, which may in turn prevent the agency from correcting serious problems,” he said.

Horowitz cited foot-dragging by the Justice Department in the IG's investigation of Fast and Furious, an operation in which the Bureau of Alcohol, Tobacco, Firearms and Explosives allowed thousands of guns to be smuggled into Mexico with the intent of tracking them to drug lords.

Many of those guns have since turned up at crime scenes, including the December 2010 murder of U.S. Border Patrol agent Brian Terry.

The IG's report, published in September 2012, slammed federal agents and prosecutors for bad judgment, including former Assistant Attorney General Lanny Breuer and former ATF Acting Director Kenneth Melson. Attorney General Eric Holder was not implicated.

IG investigators had trouble getting certain documents, including grand jury and wiretap information, after higher-ups in the Justice Department initially restricted access to those documents.

Eventually, the materials were provided after Holder or his deputy gave permission for the records to be released.

Horowitz said getting permission from agency heads is particularly difficult when that person is the potential target of an IG investigation, as Holder could have been in Fast and Furious.

Horowitz, whose answer was not specific to Holder or the Fast and Furious investigation, said he has no ability to bypass the attorney general.

Similar obstacles were described by Kathy Buller, the Peace Corps IG, whose investigation of sexual assaults of volunteers has been stymied because the agency refuses to release reports.

Buller said her office has the power to investigate the Peace Corps’ handling of the complaints, both through the 1978 law that created inspectors general and the Kate Puzey Volunteer Protection Act of 2011, which specifically gives the IG access to all official information it needs.

However, the agency's position is that it cannot release “restricted” reports to the IG because of privacy concerns.

All reports are considered restricted when they are filed unless the victim specifically opts to make them unrestricted, Buller said.

The only way her investigators can access a report is if the victim voluntarily changes its status to unrestricted.

Buller asked that Congress reiterate it meant what it said in giving the IG explicit authority to access all records in the 2011 law.

The volunteer protection act was passed because Peace Corps administrators failed to deal with reports of sexual assaults of volunteers, Buller said.

Traumatized victims “were being ignored, blamed for their assaults and their cases were being mismanaged,” Buller said.

One in eight Peace Corps volunteers reported being sexually assaulted in 2012, according to the agency, which refuses to say how many attacks occurred.

“The policy has created a blackout of information concerning restricted reports,” Buller said. “It defies common sense to imagine that Congress intended to increase OIG’s oversight duties over the Peace Corps response to sexual assaults while simultaneously curtailing its ability to access the information it needs to fulfill those duties.”

Although committee members showed bipartisan support for strengthening IG access to records, some balked at the suggestion they should have more power to compel statements.

Even the FBI cannot do that, and giving IGs that power could raise civil rights concerns, said Rep. Elijah Cummings, D-Md., ranking Democrat on the committee.