Investigations into the massive leaks of documents on the Afghan war have begun to enwrap possible civilian involvement as the White House implores the website WikiLeaks to stop posting similar files and new leaks keep on coming.

The U.S. military's criminal investigators have inquired a number of civilians from the Massachusetts Institute of Technology and Boston University, said an article published on the New York Times website Friday.

These questioned civilians are believed to have connections with Bradley Manning, a 22-year-old private and army intelligence analyst, who has already been charged with leaking classified material to WikiLeaks, including a video clip of a U.S. Apache helicopter shooting civilians in Baghdad and over 50 classified U.S. State Department cables selected from more than 150,000 pieces he illegally downloaded.

He has also been confirmed as a main suspect in the disclosure of over 90,000 Afghan war documents to WikiLeaks. However, whether these leaked papers are those posted on the website remains unclear, said the article.

The military also didn't unveil any further concrete evidence to suggest there is someone in the dark helping Manning to transfer these secret materials to WikiLeaks.

The investigators' questioning of these civilian leads may be warranted by Manning's visits to some of his friends in Boston during a home leave in January.

They believe that Manning exploited a loophole in Pentagon's computer network to download and burn secret data on compact discs over six months.

Adrian Lamo, a computer hacker who kept touches with the Private by sending instant messages this year, turned him in to the Army investigators to seek cooperation with them.

He said on Friday that WikiLeaks provided Manning with technical backing so that he could send these downloaded data through specially encrypted e-mails to avoid detection, adding that, though without direct evidence proving the connection between Manning and WikiLeaks, Manning was "manipulated" by the website.

There is no response either from the military or WikiLeaks's founder Julian Assange, an Australian national, to Lamo's words.

One of the inquired persons said he refused to be the Army's WikiLeaks watcher as he had nothing to do with the website, while another said the military is trying to set up a team encompassing Manning's friends and classmates to "infiltrate" WikiLeaks, according to the article.

The U.S. Army authorities continue to chastise the leaks as dangerous and harmful.