Updated

The former security chief at the Quantico, Va., Marine Corps base testified Wednesday that an Army private suspected of leaking U.S. secrets in the WikiLeaks case was kept tightly confined partly because another prisoner had recently committed suicide.

Marine Col. Robert Oltman spoke at a pretrial hearing for Pfc. Bradley Manning at Fort Meade, outside Baltimore. Manning's lawyers are seeking dismissal of all charges, claiming his pretrial confinement in the Quantico brig was excessively harsh.

Manning was held there for nine months in highly restrictive, maximum custody and "prevention of injury" status. He was locked up alone in a small cell during this time and had to sleep naked for several nights.

Oltman said the suicide of another detainee after his custody status was reduced made Oltman skeptical about a psychiatrist's recommendation to ease Manning's confinement conditions.

The Marine officer said he told medical staffers that Manning should remain in highly restrictive confinement unless senior officers decided otherwise.

"Nothing's going to change," Oltman testified. "He won't be able to hurt himself. He's not going to be able to get away, and our way of ensuring this is that he will remain on this status indefinitely."

Manning was later moved to Fort Leavenworth, Kansas, where he was re-evaluated and given a medium-security classification.

Supporters of the Army private, now 24, again filled the courtroom on the second day of what is expected to be a six-day hearing.

Manning faces possible life imprisonment if convicted of aiding the enemy, the most serious of the 22 charges that he faces.

He is accused of sending hundreds of thousands of classified Iraq and Afghanistan war logs and more than 250,000 diplomatic cables to the secret-spilling website WikiLeaks while he was working as an intelligence analyst in Baghdad in 2009 and 2010.

The materials Manning is suspected of leaking include sensitive reports on foreign governments and leaders and a 2007 video clip of a U.S. helicopter crew gunning down 11 men later found to have included a Reuters news photographer and his driver. The video garnered worldwide attention. The Pentagon concluded the troops acted appropriately during the attack, having mistaken the camera equipment for weapons.