Investigators have found concrete evidence on computers used by Pfc. Bradley Manning that link him with the leak of classified Afghanistan war reports, The Wall Street Journal reports.

The disclosure came as Defense Secretary Robert Gates pledged Thursday to "aggressively investigate the leak" and find ways to prevent further breaches, and told reporters that he had invited the Federal Bureau of Investigation to assist the probe.

Pfc. Manning already was charged by the military in July with illegally taking secret State Department files and disseminating a classified video, which defense officials said was the one released by WikiLeaks showing a U.S. military helicopter firing on a group of people in Baghdad. Two Reuters journalists and seven others were killed in the 2007 incident.

The 22-year-old private worked in intelligence operations in Baghdad. He was supposed to be examining intelligence relevant to Iraq, but defense officials said Pfc. Manning used his "Top Secret/SCI" clearance to tap into documents around the world.



Read the entire story at wsj.com