Adrian Lamo, the former computer hacker who first identified Bradley Manning to federal authorities as the source of hundreds of thousands of classified documents leaked to Wikileaks, was challenged by the Army private's defense over his history as a hacker, his criminal record and his problems with drugs.

Lamo was among the prosecution's final witnesses today at the pre-trial hearing that will determine whether Manning will face a court martial for allegedly leaking the classified documents.

Lamo told prosecutors how over a span of five days in late May 2010 he received a series of encrypted emails from Bradley Manning, providing him with information that suggested the sender was in the Army.

The contacts soon progressed to encrypted chats using AOL Instant Messenger, where Manning used the handle "bradass87."  Lamo said he could only speculate as to why Manning was using encrypted contacts to reach out to him.

Lamo described how he made multiple attempt to verify that the person who was contacting him was actually in the Army and in Iraq.

"At that point he made a number of claims that caused me to believe that I might be misled … and I desired authentication of the other party," he said.

He also verified that bradass87 was Bradley Manning after Manning sent him a "friend" request on Facebook and he saw information and photos on the site that matched.

Lamo, who acknowledged to prosecutors that he suffers from Asberger Syndrome and that he has a history of drug use, said that at the time he was communicating with Manning medication had reduced his symptoms and allowed him "to function more normally." He also admitted he had been a source in certain media reports.

Manning's lead attorney David Coombs then led a blistering line of questioning, focusing on Lamo's past drug use and his convictions for computer hacking.

"You are a convicted felon?" he began, to which Lamo replied: "That is correct."

Coombs  noted a string of 2007 hacks on large companies and a 2004 conviction for computer fraud. Lamos then confirmed that he had been involuntarily institutionalized in April 2010, after overmedicating on prescription drugs.

Lamo told Coombs that he had not been offered immunity in return for his testimony: "I am here to ensure that the truth is presented," he said.

What ensued was a detailed discussion of Lamo's contacts with Manning that ultimately led him to contact federal authorities  about what he had learned from Manning.

Coombs led Lamo through detailed logs of the Internet chats where Lamo established Manning's "bonafides" that he had leaked State Department cables to Wikileaks.

Coombs pressed Lamo to say whether he was peppering Manning with so many questions about his operations because he was working with law enforcement.

"I was asking these questions out of curiosity. I am a curious individual, which I believe has been amply evident by my actions in the past," he said, referring to his brushes with the law.

The defense attorney also raised concerns over Lamo having presented himself in the chats as both a journalist and a pastor.

"You state 'I am a journalist and a minister, you can pick either and consider this a confession or an interview,'" Coombs said, implying that whatever Manning revealed could then be considered privileged information.

"Yes," Lamo replied. "I also see there is no affirmative response."

That led to a testy exchange between the witness and Coombs.  Lamo said he considers himself a minister in the Universal Life Church and a journalist because he has published articles.

Earlier in the day, Manning's former supervisor testified about violent episodes he exhibited before their unit left for Iraq that led her to believe he should have never deployed.

Former Army Specialist Jihrleah Showman described multiple incidents before and during their  unit's deployment to Iraq that she said led her to  conclude he was "a threat to himself and to others." The testimony raised questions about why Manning's superior officers allowed him to deploy and continue to have access to classified materials.

Manning was reduced in rank from a specialist to a private after a May 2010 incident in Baghdad in which he punched her in the face in what she described as an unprovoked attack.

Showman described two incidents in 2009 at Fort Drum, N.Y., that made her question why he was still on the list to go to Iraq.  In one incident, she said, he approached a senior ranking non-commissioned officer "screaming at the top of his lungs, waving his hands, with saliva coming out of his mouth."

After that episode, Showman recommended to the NCO that Manning receive an Article 15 non-judicial punishment to deal with a minor infraction, because he "was a threat to himself" and a "threat to others" and had disrespected his superiors.  However, to her knowledge, superior officers took no action.

In the other incident she remembered seeing  Manning freeze when a lieutenant asked him a question. When  Showman and the NCO later met with Manning to see what might be wrong, she said, he revealed that he "constantly felt paranoid" and "felt people were listening to his conversations, felt he could not trust anyone in the unit or around him."

She described herself as being "furious" when she saw Manning's name on a deployment roll.

While deployed to Iraq in December 2009, Showman said she witnessed a counseling session between Manning and Sgt. Daniel Padgett in which Manning became violent.  She said Manning stood up, flipped a table and then went towards Padgett.  Showman said Manning appeared to look around the room and spotted an M4 carbine in the corner. Convinced that he was going toward the M4, Padgett grabbed him from behind  in a lock-hold and dragged him to a chair.  Again Manning did not receive an administrative punishment.

Manning's defense attorneys are expected to call three witnesses on Wednesday when the hearing resumes.  Final arguments could come right after that.