But an Army investigation has concluded that the commanders' decision not to heed the specialist's advice and their failure to properly discipline Manning may have contributed to one of the most high-profile classified military network breaches in decades, the military official said.
Manning, 23, an intelligence analyst, has been accused of downloading classified State Department and Pentagon files onto his personal computer. Last summer, he was charged with transmitting classified material to an unauthorized person.
The Army investigation, which is separate from an ongoing criminal inquiry, found that Manning's immediate supervisors did not follow procedures for overseeing the secure area where the classified information was kept, greatly increasing the risk of a security breach, the official said.
The investigation, which was conducted by Lt. Gen. Robert L. Caslen, the senior Army commander at Fort Leavenworth, Kan., was ordered by top Pentagon officials to determine how the breach occurred and whether broader institutional failings allowed Manning to allegedly download the documents.
Caslen is expected to relay his findings to the Army secretary this week and to Defense Secretary Robert M. Gates in mid-February, military officials said.
"There were serious leadership failures within the unit chain of command and gross negligence in the supervision of Pfc. Manning in Iraq," said a second official who is familiar with the Army probe.
The defense officials were not authorized to speak about the inquiries. An Army spokesman declined to comment on the criminal investigation of Manning or on Caslen's investigation of how the leak took place.
Manning lived in Potomac before joining the Army in 2007. The military was facing a shortage of intelligence analysts in Iraq when he was deployed there in 2009.
The internal Army investigation did not fault Manning's recruitment to the Army or the initial decision to grant him a security clearance, said the official familiar with the probe.
"Something happened in his personal life after he joined the Army," the official said.
A source familiar with Manning's mental health records indicated that the stress that led the soldier to seek help was caused primarily by a faltering personal relationship.
At Fort Drum, Manning balled up his fists and screamed at higher-ranking soldiers in his unit, said the official familiar with the Army inquiry. In Iraq, a master sergeant who supervised Manning was so concerned about the private's mental health that he disabled Manning's weapon in December 2009, the private's attorney, David E. Coombs, previously said. Also in Iraq, in May 2010, Manning was demoted a rank for assaulting a fellow soldier, the Army said.