Washington ? The teenager accused of participating in the sniper attacks that terrorized the Washington region has told investigators that he pulled the trigger in several of the shootings, three law enforcement sources said Saturday.

During an interrogation that lasted about seven hours, John Lee Malvo provided details about several of the slayings that authorities have linked to him and John Allen Muhammad, including killings in Fairfax and Prince William counties in Virginia and in Washington, D.C., the sources said.

One law enforcement source said Malvo said he fired the shot that killed FBI analyst Linda Franklin at a Home Depot store in Fairfax County, for which he has been charged with capital murder.

In the interviews after he was transferred to Fairfax County on Thursday, Malvo, 17, told investigators that the shootings were well-planned and involved scouting missions. Sources said that Malvo described himself and his partner as behaving like soldiers: One would be a lookout and communicate with the other on two-way radios.

If conditions, like traffic, were not right, they would not shoot, Malvo told investigators. They deliberately hopped from jurisdiction to jurisdiction to create confusion, and they watched the news coverage of their crimes, the sources said.

Malvo was talkative, smiling, even bragging in response to indirect questions from investigators, sources said, but he was adamant in refusing to talk about Muhammad or to even mention his name, using “we” a lot. Muhammad, 41, deflected police efforts to interrogate him in Prince William County, maintaining his silence for hours and even refusing to give up his name to a booking clerk.

The law enforcement sources spoke only on condition that they not be identified. They would not provide further details of the Malvo interrogation and would not identify the other shootings that Malvo allegedly described.

Muhammad and Malvo have been charged or named as suspects in 21 shootings across the country in which 14 people were killed and seven wounded.

The spree allegedly touched the West Coast, the deep South and the Washington region, including shootings in Maryland, Virginia, the District, Washington state, Alabama, Louisiana and Georgia.

Prince William County Commonwealth’s Atty. Paul B. Ebert said Saturday that he didn’t want to comment on Malvo’s statements.

“I’m not going to comment on the evidence,” Ebert said. “As I’ve said all along, we have a prosecutable case.”

Fairfax County Commonwealth’s Atty. Robert F. Horan Jr. did not return a call seeking comment.