WASHINGTON - The U.S. Army has launched a wide-ranging investigation into how a private suspected of downloading thousands of secret reports and diplomatic cables and handing them over to WikiLeaks was able to do so and whether other soldiers should face criminal charges in the case, McClatchy Newspapers has learned.

The Army confirmed the investigation, but it would not release details.

An Army official familiar with the investigation said that the six-member task force had been given until Feb. 1 to complete a report that would look at everything from how Pfc. Bradley Manning was selected for his job and trained to whether his superiors missed warning signs that he was downloading documents he had no need to read.

The report could change how the Army - the largest distributor of government security clearances - grants access to government documents as well as lead to recommendations of charges against soldiers who worked with Manning and may have been aware of his activities.

It is the second time in two years that Army procedures had been the subject of intense internal investigation.

A similar probe was undertaken after an Army psychiatrist allegedly opened fire on fellow soldiers at Fort Hood, Texas, in November 2009, killing 13.

That investigation focused, in part, on how superiors failed to notice signs that Maj. Nidal Hassan, who had exchanged e-mail with a radical Yemeni-American cleric, might turn violent. The probe resulted in dozens of changes in Army procedures.

Manning, now 23, was an intelligence specialist in Baghdad during 2009 and the early months of 2010 when he allegedly downloaded hundreds of thousands of classified documents.

Those documents reached WikiLeaks - Army officials have said they are not certain how - and have been published by the website in four separate bursts that began in April with the release of a video showing an Army helicopter firing on civilians in Baghdad, killing two Reuters news agency employees.

The website also released tens of thousands of documents related to the wars in Iraq and Afghanistan before the current, ongoing publication of hundreds of thousands of State Department cables, which began Nov. 28.

Manning allegedly downloaded the documents while pretending to listen to music by Lady Gaga on headphones, a cover story, investigators say, to explain the sound of the computer's CD drive whirring as he copied the files.

He is being held in solitary confinement at the Quantico Marine Base in Virginia on charges that could lead to a prison sentence of up to 52 years.

Some human rights groups charge that Manning is being mistreated, with no ability to exercise or access to news. The Defense Department has denied the claims.

Army Lt. Gen. Robert Caslen Jr., the commander of the Army General Command and Staff College at Fort Leavenworth, Kan., will lead the study, which was ordered by John McHugh, the Army secretary.

"Lt. Gen. Caslen has a very broad investigative mandate, and he has been assured of the cooperation of both the Department of the Army and the U.S. Central Command as he proceeds. Lt. Gen. Caslen's investigation will not interfere nor conflict with the ongoing criminal investigation," Army spokesman Lt. Col. Christopher Garver said in a statement prepared in response to questions.

No other service branch is conducting a similar investigation, but the Army findings could lead to changes throughout the military. With more than 800,000 uniformed personnel, the Army issues more security clearances than any other government organization.

The Justice Department also is investigating the possibility of bringing charges against WikiLeaks founder Julian Assange.