Before the online site WikiLeaks published a trove of classified documents about the Afghanistan war, government investigators interviewed Boston-area acquaintances of a military analyst charged with providing other documents to the site in an effort to prevent additional leaks, according to one person interviewed in the probe.

The investigators from the Army and the State Department seemed to be "looking for classified documents that they thought to be in the Boston area," said the acquaintance, who would discuss the sensitive matter only on the condition of anonymity. "I got the impression they were still in the process of containing a leak."

The man, a computer expert who met Pfc. Bradley E. Manning in January, said he told the investigators in mid-June that he knew of no such documents.

The interview was among at least two investigators conducted in the Boston area after Manning was accused of giving WikiLeaks State Department cables and a video of a helicopter attack in which unarmed civilians were killed in Baghdad. Officials have said they are investigating whether Manning leaked the Afghanistan documents made public last week, a disclosure that prompted condemnation from the Obama administration.

The computer expert also said the Army offered him cash to, in his word, "infiltrate" WikiLeaks. "I turned them down," he said. "I don't want anything to do with this cloak-and-dagger stuff."

Army Criminal Investigation Division spokesman Chris Grey declined to comment on the claim. "We've got an ongoing investigation," he said. "We don't discuss our techniques and tactics."

Another Manning acquaintance who was questioned said investigators "assumed that he was the one who did it and were trying to understand why, what was going on with him psychologically, to either make it so nobody gets to this point in the future or spot people who've gotten to this point and make sure they didn't do any damage."

This acquaintance, also a computer expert who spoke on the condition of anonymity, is affiliated with the Massachusetts Institute of Technology. He said he was interviewed twice in June in Cambridge, Mass., shortly after Manning was detained. Manning was charged in July.

Manning, who lived in Potomac and was stationed at Fort Drum, N.Y., before shipping out to Baghdad last year, had hoped he would serve his time and then use the G.I. Bill to go to college. His military attorney has declined to comment.

"He was definitely interested in making a positive impact on the world," said Danny Clark, a friend of Manning's who runs a small tech firm in Cambridge and has declined to be interviewed by military investigators.

Meanwhile, friends and family are raising money for Manning's defense, including a private lawyer to augment the Army-provided defense lawyer. The San Francisco-based war resisters' group Courage to Resist has raised $11,418 and is aiming for $100,000, assuming a "sizable contribution from WikiLeaks," said Jeff Paterson, project director.

Manning has been transferred from Kuwait, where he had been detained, to Quantico. He was charged in military court in July and will have a preliminary hearing to determine if he should face a court-martial.

Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, is scheduled to appear on NBC's "Meet the Press" and CBS's "Face the Nation" on Sunday to further denounce WikiLeaks for endangering the lives of U.S. troops and Afghan civilians. White House officials are concerned that more potentially damaging information could be released by the group in the coming weeks.

One senior military official balked at a suggestion by Defense Secretary Robert M. Gates that the WikiLeaks disclosure could cause the Pentagon to limit the distribution of classified information to combat field units, where it is harder to monitor what analysts are downloading.

"Limiting intelligence to troops in combat is a non-starter," said the official. "It doesn't make sense to use WikiLeaks as a reason to limit information to the troops who need it." Such limits could "get soldiers killed," the official said.

The classified computer systems in Iraq and Afghanistan don't have the same safeguards that exist in the United States. "In the States, there are rack and scoring servers that watch where analysts go," the official said. At the time of his arrest, Manning was an intelligence analyst at a relatively small base in Iraq.