Updated at 11:50 a.m. EST
Defense Secretary Robert Gates will announce a Pentagon-wide investigation of the Fort Hood shooting, a defense official confirmed to CBS News.
The official told CBS News correspondent Kimberly Dozier that the department's review will supersede the Army's internal probe, which was reported by CBS News Monday.
Gates' staff was upset about the report of the Army investigation because it highlights Gates' lack of trust in the Army to do the job properly, the official told Dozier.
Gates and Adm. Mike Mullen, the chairman of the Joint Chiefs of Staff, were wrestling with a list of retired senior defense officials in deciding who to lead the investigation, reports Dozier.
Gates will announce Thursday that it will be a single, coordinated review, and will call for a quick, short-term report, followed by a longer, more extensive study, an administration official told the Associated Press.
Components of the wide-ranging probe could include self-examinations by the Army and the military's medical community, and likely look at personnel policies and the availability of mental health services for troubled troops.
It would go well beyond the specific case of Maj. Nidal Malik Hasan, the Army psychiatrist accused of killing 13 people and wounding more than 30 in the shootings at the Texas military post on Nov. 5.
The official spoke on condition of anonymity because announcements have not yet been made. The identity of the former official leading the review was not revealed.
Details were still being worked out Wednesday night, but the review would mirror other department inquiries during Gates' tenure, including a probe of the Air Force's handling of nuclear materials.
President Barack Obama already has ordered a review of all intelligence related to Hasan, including his contacts with a radical Islamic cleric overseas and concerns about the major voiced by some medical colleagues, and whether the information was properly shared and acted upon within government agencies.
At a Senate Judiciary Committee hearing Wednesday, Attorney General Eric Holder said he was disturbed to learn that the Hasan had communicated the radical Islamic cleric.
Investigators have said e-mails between Hasan and the imam, Anwar al-Awlaki, did not advocate or threaten violence. After the shootings, al-Awlaki's Web site praised Hasan as a hero. Holder said investigators still were gathering evidence in the case.
At the hearing, Holder was asked what he would do to prevent such an occurrence in the future.
"I think what we have to do is understand exactly what happened that led to that tragedy," Holder said. "Were their flags that were missed? Were there miscommunications or was there a lack of communication? And once we have a handle on that, I think that we can propose and work with this committee on ways in which we can prevent such a tragedy from occurring again."
"I will say that on the basis of what I know so far, it is disturbing to know that there was this interaction between Hasan and - and other people that is, I find, disturbing," Holder said.
As Congress prepared to open oversight hearings into the massacre, Rep. James Langevin, D-R.I., said Wednesday there was no suggestion that Hasan was working with others. "All the information we have is that this is a lone wolf," Langevin, a member of the House Armed Services Committee, said after a closed-door briefing on the Fort Hood investigation.
Sens. Susan Collins, R-Maine, and Joe Lieberman, a Connecticut independent, are investigating whether a breakdown in communications or poor judgment calls contributed to the shootings, considered the deadliest attack on a military base in the U.S. The Senate Homeland Security Committee that Collins and Lieberman sit on was expected to open hearings in the case Thursday.
A joint terrorism task force overseen by the FBI learned late last year of Hasan's repeated contact with the cleric, who encouraged Muslims to kill U.S. troops in Iraq. The FBI said the task force did not refer early information about Hasan to superiors because it concluded he wasn't linked to terrorism.
"The Fort Hood massacre also raises questions about whether there are unnecessary restrictions on information sharing and whether those restrictions resulted in a failure to trigger a further inquiry," Collins said.
Hasan's psychiatry supervisors at Walter Reed Army Medical Center had expressed concerns in May 2007 about what they described as Hasan's "pattern of poor judgment and lack of professionalism." The Associated Press had previously reported that doctors there discussed concerns about Hasan's overly zealous religious views and strange behavior months before the attack, but National Public Radio on Wednesday published an evaluation letter signed by the department's psychiatry residency program director, Maj. Scott Moran.
Moran concluded that Hasan still could graduate and did not deserve even probation because Hasan was able to improve his behavior once confronted by supervisors. About a year after Moran's memo was written, Hasan was selected for promotion from captain to major, a position that would give him increased pay and responsibilities. He would formally become a major in May 2009 and by July he was on his way to Fort Hood.
Rep. Tom Rooney, R-Fla., said any "telltale signs that he was a disgruntled major were not as apparent as the rumors you've heard." Rooney spoke to reporters after he left Wednesday's classified briefing.
Rooney, a member of the House Armed Services personnel subcommittee and a former Army lawyer, also said Hasan was qualified to be promoted but was in "more toward the bottom third of his class."