A Fairfax County man admitted yesterday that he was the person on the other end of the line with the cell phone bandit, acting as her lookout and getaway driver as they robbed four Northern Virginia banks.

Dave C. Williams, 19, pleaded guilty in federal court in Alexandria to conspiracy to rob four Wachovia banks, including one in Vienna where he used to work. He agreed to forfeit a 1997 Acura Integra, a 42-inch plasma flat-screen television set, 11 Louis Vuitton and Coach purses and other items bought with the more than $48,000 taken in the robberies.

Williams, from the Fairfax City area, wore an oversize white T-shirt and tan trousers as he stood quietly before U.S. District Judge Gerald Bruce Lee with his attorney, Michael F. Devine. Williams said nothing other than "Yes, your honor" and "No, your honor" as the judge asked him questions to discern whether Williams knew what he was doing in pleading guilty to the two federal felonies, including a gun charge.

Holding up the prosecution's statement of facts, Lee asked Williams: "Do you admit that this is what you did?"

"Yes, your honor," he replied.

Williams faces up to five years in prison on a charge of conspiracy and a maximum sentence of life in prison on the gun charge. The gun charge carries a mandatory minimum term of seven years. Devine told the judge that federal sentencing guidelines suggested a sentencing range of 11 years and three months to 12 years and three months, although those guidelines are not mandatory.

Lee set sentencing for Feb. 24. Williams is being held without bail in the Alexandria jail.

Candice R. Martinez, 19, originally from Santa Fe, N.M., was arrested on suspicion of being the woman who robbed the four banks. She also is being held without bail at the Alexandria jail. She was arrested about 10 hours after Williams, at a house in Centreville. Authorities said it appeared she had been planning to flee to Texas or New Mexico.

A magistrate judge ordered Martinez's case submitted to a grand jury for possible indictment.

Williams and Martinez met while both attending Northern Virginia Community College, Williams's mother has said. They began dating and recently moved into an apartment together in Chantilly.

After surveillance photos of a young woman robbing a bank while chatting on a cell phone were published and aired nationwide, investigators were quickly tipped off to Martinez's identity. They searched the pair's apartment Nov. 12, seizing $3,500 in cash, still wrapped in Wachovia Bank bands, various items of consumer electronics and a Circuit City receipt for $3,685.21, according to court records.

Investigators contacted Williams on Nov. 14, and he agreed to be interviewed, an FBI agent testified last month. He was released for several hours, then arrested later that evening.

The agent, Thomas Pak, said Williams admitted being involved in all four Wachovia holdups: in Vienna on Oct. 12, Manassas on Oct. 21, Springfield on Oct. 22 and Ashburn on Nov. 4.

Williams told investigators that the pair picked Wachovia because he had once worked at Wachovia's branch on Route 123 in Vienna and was familiar with its internal workings, court records filed yesterday said.

Williams reported that the demand note he helped prepare for the robberies stated, "Give me money from the 1st, 2nd and 3rd drawer or we will shoot you or a person close to you."

Court records also show that Williams provided a handwritten statement.

"I and Candice Martinez robbed four Wachovia banks," he wrote, not only describing the note that the duo prepared for each holdup but also acknowledging that "in each robbery Candice stayed on a cell phone talking to me outside in the car."

Williams also wrote, "Candice displayed a .38 cal revolver I gave her in the last robbery" in Ashburn. The gun, which was flashed to the teller from inside the robber's purse, was not used. But its presence led to the more severe penalty Williams now faces.

In his plea agreement, Williams also consented to make restitution for the amount stolen from the banks, which authorities said was $48,620. Devine said the property recovered from Williams would be credited toward that amount.

Prosecutors said the proceeds of the robbery also went toward a Sony large-screen television set, two CD/DVD players and a four-piece bedroom set. Price tags were still attached to many items of clothing, prosecutors said.

Williams was not given the opportunity to offer any explanation or comment on his case.

Devine said that Williams "is very sorry for what he did and takes responsibility for it. He's depressed, but he knows he had to be punished."

Dave C. Williams said he was the Wachovia bank robber's driver.