In response to mounting evidence that detainees in U.S. military custody were badly abused in Iraq and elsewhere, the Pentagon has launched an array of investigations, assessments and reviews aimed, officials have insisted, at exposing those responsible for the misdeeds and preventing recurrences.

But a close look at what is being investigated, and who is doing the investigating, reveals gaps in the web of probes as well as limitations on the scope, with none of the inquiries designed to yield a complete picture of what went wrong or address suspicions of a possible top-secret intelligence-gathering operation that may have helped set the stage for the misconduct.

"I can't tell if all the inquiries represent attempts to patch new holes opening in the boat every day, or if they're part of some carefully designed strategy to have lots of activity going on around the center of this thing without probing the center itself," said John Hamre, who served as deputy secretary of defense under President Bill Clinton and now heads the Center for Strategic and International Studies in Washington.

With one inquiry completed and five more underway -- not to mention dozens of criminal investigations into alleged abusive treatment of detainees inside and outside military-run facilities -- Pentagon officials continue to promise that all trails will be pursued wherever they lead and that the guilty will be held accountable.

But some military lawyers, lawmakers and defense experts point to what they see as fundamental shortcomings: Most of the probes involve the Army investigating itself, they say, and each investigation is focused on only one aspect or another of the burgeoning scandal -- the role of military intelligence personnel who served as interrogators, for instance, or the adequacy of training of reservists or the need for revisions in Army training and doctrine.

No investigating authority has been given the specific task of assessing the roles of top authorities either in the U.S. Central Command or at the Pentagon. In past high-profile cases, including the 1991 Tailhook scandal, the 1996 bombing in Saudi Arabia of an Air Force barracks and the 2000 attack in Yemen on the USS Cole, inquiries conducted by the affected military branches were criticized by investigators from outside the services for focusing on lower ranks and neglecting to assess supervision up the chain of command.

"I really doubt whether the Defense Department can investigate itself, because there's a possibility the secretary himself authorized certain actions," said Wayne A. Downing, a retired four-star Army general who headed a Pentagon task force that examined the Air Force barracks case. "This cries out for an outside commission to investigate."

The closest the Pentagon has come to initiating an overarching independent review of detainee treatment is Defense Secretary Donald H. Rumsfeld's appointment May 7 of a four-member panel to help advise him. The panelists include two former defense secretaries (James R. Schlesinger and Harold Brown), a retired Air Force general (Charles A. Horner) and a onetime Republican House member from Florida (Tillie Fowler).

Schlesinger, the panel's chairman, said in a brief interview yesterday that the roles of top commanders, the possible involvement of government intelligence agencies and other key issues will be studied. But the panel has just two months to draft a report, and its charter calls only for identifying gaps in existing inquiries and recommending changes in training, organization and policies related to the handling of detainees.

In Congress, too, the investigative effort has yet to match major probes of the past. Republican leaders have resisted calls from Democratic lawmakers to establish a special panel of inquiry, as was done in the Iran-contra scandal of the 1980s, or authorize a blue-ribbon commission, like the one now investigating government mistakes related to the terrorist attacks of Sept. 11, 2001.

Instead, congressional action has been kept within regular committee channels, principally the armed services committees. And only the Senate committee, under the leadership of John W. Warner (R-Va.), has shown investigating vigor, convening a series of hearings that some senior House Republicans have complained are ill-advised and serve only to give more political ammunition to critics of the Bush administration.

The Senate inquiry has been hampered by the Pentagon's failure to provide it with a complete copy of Army Maj. Gen. Antonio M. Taguba's report examining abuses at Iraq's Abu Ghraib prison. After protests from committee staff last week, the Pentagon attributed the omissions to technical glitches and pledged to supply the missing pages. Although Warner has said he believes the department is working in good faith with the committee, some congressional staff members suspect the Pentagon withheld particularly sensitive documents.

"We need a master commission," said Eugene R. Fidell, a prominent lawyer who handles defense cases. "This is a very grave set of issues. The country's international reputation is on the line."

Pentagon officials defended the investigations undertaken so far as sufficiently empowered to probe where necessary, including up the Central Command chain and into the upper reaches of the Pentagon.

"My understanding is that the investigators will take their investigation wherever it leads them," Lawrence T. DiRita, the Pentagon's chief spokesman, said at a news conference yesterday. ". . . There's certainly no predetermined level above which the investigators -- are off-limits to the investigators."

As proof the military can credibly investigate itself, defense officials point to Taguba's work. Completed in April, his report has drawn widespread praise for its thoroughness and integrity.

But Taguba's charter was limited to looking at the 800th Military Police Brigade and its management of detention facilities in Iraq. Although Taguba implicated some military intelligence personnel in the abuses, he did not pursue those leads, nor -- as he told the Senate -- did he interview U.S. military authorities above the level of brigade commander. Among those not interviewed was Lt. Gen. Ricardo S. Sanchez, the commander of U.S. forces in Iraq, who ordered the inquiry.

A separate investigation, initiated in late April and headed by Maj. Gen. George R. Fay, is looking into the role of military interrogators. But Fay serves as deputy to the head of Army intelligence, which puts him in the chain of command of the units he is investigating.

The Army has two other inquiries underway. Since February, the service's inspector general, Lt. Gen. Paul T. Mikolashek, has been reviewing doctrine and training associated with detention operations throughout the U.S. Central Command area. Preliminary findings have cited problems in training, organization and doctrine but no "pattern of abuse" of detainees in Iraq and Afghanistan, according to Senate testimony this month by Gen. John P. Abizaid, the head of Central Command.

Additionally, since March, the inspector general of the Army Reserve, Col. Beverly Ertman, has been assessing the training given military police and intelligence personnel on the laws of land warfare, ethics, leadership and Army values.

Earlier this month, the Navy's inspector general, Vice Adm. Albert Church, received orders to look at operations at two prisons outside Iraq and Afghanistan holding terrorist suspects -- the detention facility at Guantanamo Bay, Cuba, and the naval brig at Charleston, S.C.

Apart from those administrative reviews, the Army's Criminal Investigation Division is pursuing dozens of alleged abuse cases in Iraq and Afghanistan. Army officials said Friday that of nine open cases involving prisoner deaths since 2002, eight were determined by medical examiners to be possible homicides, involving acts committed before or during an interrogation. Investigators also are looking into an additional 42 potential cases of misconduct against civilians that occurred outside detention facilities in Iraq and Afghanistan.

Regarding the abuses at the Abu Ghraib prison, criminal charges have been brought against seven military police reservists but not against any military intelligence personnel, although the military guards say they acted under the direction of intelligence soldiers.

A senior Army officer with direct knowledge of the criminal probes said at a Pentagon briefing Friday that investigators have targeted military intelligence personnel. But responsibility for bringing charges rests with field commanders, he added.

Concerned that his client and other lower-ranking soldiers charged so far will end up shouldering all the blame, Gary Myers, a civilian military lawyer representing Staff Sgt. Ivan L. "Chip" Frederick II, requested a special "court of inquiry" earlier this month. Such an inquiry, consisting of senior officers outside the chain of command at issue, was convened after a U.S. Navy submarine collided with a Japanese fishing boat near Hawaii in 2001.

But Lt. Gen. Thomas F. Metz, the convening court-martial authority in the Abu Ghraib case, rejected the idea, informing Myers he saw no legal basis for it.

President Bush and other senior administration officials continue to portray the abuses largely as isolated incidents carried out by a small number of soldiers. But some defense experts suspect that the Pentagon may be trying to prevent investigations from exposing the possible existence of a secret intelligence-gathering effort that either overlapped with some of the publicized abuses or operated in the same combat zones.

An article in the New Yorker magazine this month by Seymour Hersh reported that as part of the administration's war on terrorism, Rumsfeld established a highly classified "special access program" aimed at capturing and interrogating "high value" individuals. The Pentagon has not confirmed such a program.

"Every intelligence operation has a breakaway point, where you try to protect the organization with a cover story," Hamre said. "What some people are saying is that the Pentagon is still trying to keep the breakaway line at the rogue-soldier level."

Others pointed to less covert factors that are complicating decisions by both the administration and Congress on how to investigate the detainee scandal.

"One thing that makes this unusual is that it is happening in wartime, where the results have the potential of affecting the war itself," said Peter D. Feaver, a professor of political science and public policy at Duke University. "The other factor is the presidential election. Any investigating commission set up now might get sucked into a partisan fight."

Rumsfeld and other senior defense officials also warned several weeks ago, as news of the abuses began to emerge, that the Pentagon ability's to investigate -- and publicize what it finds -- would be constrained by the need to avoid trampling on rights of the accused and jeopardizing future prosecutions.

Nonetheless, members of the outside panel set up by Rumsfeld say they intend to make their study as comprehensive as possible and to take advantage of the defense secretary's pledge to provide whatever documents and interviews with Pentagon personnel they request.

"We'll probably be doing some kind of timeline to start with -- who knew what when," said Fowler, one of the four members. "Each of us is pretty independent. The one thing you can be sure of from us is, ours will be a really thorough and reasoned review."

Staff writers Scott Higham, R. Jeffrey Smith and Joe Stephens contributed to this report.