Steven A. Stefanowicz was a towering high school athlete in this Philadelphia suburb; at 6-foot-5, he was the tallest member of the Souderton Area High School class of 1988 and the grandson of a Marine. He graduated from the University of Maryland in 1995 with a bachelor of science degree. Three years later, he joined the Navy Reserve and learned the intelligence craft, a skill he brought to the private sector.

Before Navy postings in Afghanistan and Oman, he sold Jet Skis in the Florida panhandle town of Panama City, befriending a former prison corrections officer with whom he discussed interrogation techniques. He worked as an information technology headhunter in Australia and dated a woman there who recently called him a "gentle giant" in an interview with an Australian newspaper.

The former Navy intelligence specialist -- now a civilian interrogator with Arlington-based CACI International Inc., a defense contractor -- was implicated this month in the abuse at Abu Ghraib prison in Iraq, which came to light with the publication of photographs showing unclothed Iraqi inmates forced to pose in humiliating positions.

In interviews Thursday, Stefanowicz's lawyer, mother and friends said he was wrongly accused in Army Maj. Gen. Antonio M. Taguba's report, which said Stefanowicz lied to military investigators about alleged prison misdeeds and ordered or allowed military police to physically abuse prisoners.

"The only source of any allegation against him are the six lines in the 53-page report. And those six lines are not only vague, but completely unsubstantiated," said Henry E. Hockeimer Jr., in his office at Hangley Aronchick Segal & Pudlin in Philadelphia on Thursday. "He did nothing wrong, nor is he aware of any wrongdoing whatsoever by any CACI employee."

CACI has not acknowledged Stefanowicz's employment but said it has not fired anybody as a result of the Army investigation. Neither CACI, his lawyer nor his mother would say where he is. His mother said she would not discuss his location because she feared for his safety.

Taguba recommended that Stefanowicz's military security clearance be revoked and his job terminated. The report names Stefanowicz and three other men as "either directly or indirectly responsible for the abuses at Abu Ghraib."

At Stefanowicz's childhood home here, a split-level in front of which was a sign reading "No Trespassing Or Comment," his mother stood up for him.

"My son's not capable of doing anything like that," Jean Campbell said during a 90-minute interview in her back yard.

Campbell, who is divorced from Stefanowicz's father and remarried, said her mailbox has been filled with hate mail in recent days. "The world should apologize to my son for accusing him when they didn't know him . . . didn't know anything about him," she said.

Stefanowicz, 34, has become a symbol of the public-private side of the war in Iraq, where civilian contractors -- many of them former soldiers, sailors and Marines -- work with military personnel and play an increasingly important role in the fighting and occupation. Stefanowicz was one of several civilian interrogators employed at the Abu Ghraib prison.

"He was arguably one of the best that we had. He was able to get results. He was able to understand who it is he was working with," said Army Chief Warrant Officer John D. Graham, who was an interrogation operations officer at Abu Ghraib from late July to early January. Graham was not mentioned in the Taguba report.

He would talk only about Stefanowicz and declined to comment on the investigation at the prison and the allegations of abuse there.

Stefanowicz "had lots of good innovative ideas about how we can talk to people and extract information. He was very perceptive in his conversations with detainees," said Graham, who frequently dined with Stefanowicz and said he never saw him give orders to soldiers.

At one point, Graham said, Stefanowicz questioned the manner in which military police were treating prisoners.

"He came to me and voiced some concerns about certain things going on, concerning treatment of the detainees," Graham said. "We brought those issues to a higher-up and somebody who works with us went over to talk with the [military police] to see what was going on."

Stefanowicz arrived at Abu Ghraib in October 2003 and took charge of CACI's team in late 2003, Graham said. At one point, Stefanowicz acted as a liaison between CACI's employees and the military, Graham said.

In the first months, Stefanowicz's interrogation teams included a translator and an Army interrogator. Because of staffing shortages, they were later reduced to two-person teams, Graham said, but Stefanowicz never interrogated a prisoner alone. Graham didn't know whether Stefanowicz had interrogation training, but said it seemed that he had.

"What Major Taguba had said didn't match anything I had observed with Steve -- didn't sound like Steve at all," Graham said.

Graham left Abu Ghraib in January and is now stationed in the United States.

Stefanowicz is the second of four children. As a child, he showed a fondness for military books, said his mother, who forbade her three boys from playing football, deeming it too dangerous.

He was the center on his high school basketball team, despite an eighth-grade operation to correct a difference in the length of his legs, a condition that kept him out of the Marines.

He graduated from the University of Maryland in 1995, according to school records. In 1998, he joined the Naval Reserve and was assigned to the Naval Reserve Joint Intelligence Center in Jacksonville, Fla., until February 2001. During his time in Florida, he was a salesman at Jet Wheels Inc. in Panama City, selling recreational vehicles such as motorcycles and Jet Skis.

There he made friends with Richard Shockley, a former corrections officer and a customer of the store. "Steve used to ask me a lot of stuff about inmates and how you talk to them and stuff," Shockley said. "Steve didn't bring himself off as an interrogating person. He was real easy-going, was real well-liked around here."

Stefanowicz left Panama City for Afghanistan in March 2000 for several weeks, Shockley said. After his return to the United States, he left again, for Australia, where he continued his Navy Reserve service while working in the technology sector.

Stefanowicz came home soon after the terrorist attacks of Sept. 11, 2001, and volunteered for active duty before his reserve unit was called up, his mother said.

In February 2002, he was sent to Muscat, Oman, where he was stationed until February 2003. Last September he left his final posting at Willow Grove Naval Air Station, only minutes from his mother's home in Pennsylvania.

He left for Baghdad as a CACI employee in October. Campbell said she rarely heard from her son after he arrived in Baghdad and even when they did talk, he never told his family much. "And we know not to ask 'cause he's not going to tell," she said.

Not long after he arrived at Abu Gharib, however, he sent a wish list home to his mother. It included SpaghettiOs and "a lot of rat poison" because the prison was infested, he said.

Ahrens reported from Washington.