He is accused of 21 charges, including aiding the enemy, and could face life in prison without parole if convicted in the case. Manning is charged with downloading intelligence documents, diplomatic cables and combat videos and forwarding them to WikiLeaks.
National Security Agency contractor Steven Buchanan and David Shaver told the court-martial they had traced breaches of the U.S. government's secret Intelink intelligence database to Manning's user name and Internet Protocol address. Prosecutors are trying to prove that Manning orchestrated the release of documents, including secret diplomatic cables.
Defense attorney David Coombs asked if the more than 800 Internet searches from Manning's computer could have resulted from malfunctioning equipment, or activity by other people. Shaver said that this was true.
Military computer crimes investigator Mark Mander said he used Internet searches to link leaks of classified information to WikiLeaks. The sites displayed chat logs that show when internet users post information and his review showed a large amount of classified US military information was transferred without authorisation.
Defence attorneys have attempted to prove the evidence was weak as there was no proof that Manning personally viewed the Tweets. Mander also acknowledged Manning never displayed anti-American sentiments and did not find anything that indicated he wanted to help the enemy.