Authorities arrested the woman they believe to be the so-called "cell phone" bank bandit early this morning in Centreville, Va., after an FBI agent spotted her car.

An FBI spokeswoman, Debbie Weierman, said Candice R. Martinez, 19, was taken into custody without incident about 4 a.m. at a residence in Centreville where the car was parked. She is being held on a warrant for armed robbery in the Fairfax County jail.

Martinez is a resident of Chantilly, Va. Authorities did not say who lived in the Centreville home.

Fairfax and Loudoun county authorities said yesterday they had identified the mysterious woman with the phone glued to her ear in a series of Northern Virginia bank robberies. But, they said at that time, they did not know where she was.

Police charged Martinez in warrants Saturday with bank holdups in Springfield and Ashburn, two of four robberies committed in recent weeks by a young woman who carried on cell phone conversations while demanding cash from Wachovia bank branches.

According to an affidavit filed by the FBI, Martinez confessed to the four robberies, the Associated Press reported. Her boyfriend, Dave C. Williams, 19, also confessed to driving the getaway car, the news agency reported. It reported that court papers said Williams once worked at one of the banks that was robbed.

Weierman said law enforcement had issued a lookout for Martinez's car about 2 a.m. this morning. They believed she might be heading out of town, to New York or Texas or New Mexico.

At 3:40 a.m., an FBI agent driving alone in Centreville in connection with the case saw the car, in which two men were sitting. He took them into custody, called for backup from the Fairfax County police.

After they arrived, a police spokesman said, they surrounded the home. When police arrived, they surrounded the house on Pickett Oaks Road and called for the occupants to surrender, police spokeswoman Mary Mulrenan said. One by one, several people emerged, including Martinez, and she was taken into police custody.

Martinez was questioned for about six hours at Fairfax police headquarters this morning by robbery detectives before being taken to the county jail for booking. Her first court appearance will likely be tomorrow morning.

In a brief telephone interview last night, a woman who identified herself as Martinez's stepmother said: "She's a good girl. She comes from a good home."

The woman, who was reached at her home in Santa Fe, N.M., and who identified herself as Jackie Martinez, said the matter was "overwhelming for the whole family."

After searching the suspect's Chantilly apartment Saturday night, detectives waited for Candice Martinez over the weekend, but she did not go home. So police again turned to the public yesterday for help in capturing the cell phone bandit.

Tips from the public -- after photos and video footage of the bandit were published and broadcast nationwide -- led authorities to Martinez, court records show. Fairfax police said their Crime Solvers tip line received more than 30 calls Friday after the images were shown, including remarkably clear surveillance video of the woman at a teller's window in Ashburn.

The first robbery took place Oct. 12 in Vienna, at the Wachovia branch at 212 E. Maple Ave. The second was Oct. 21 in Prince William County, at 8441 Sudley Rd. in the Manassas area. The next day, the branch at 7030 Old Keene Mill Rd., Springfield, was robbed.

Detectives showed a surveillance photo from the Prince William holdup to a Springfield teller. "That's her," he said. Police were not able to get photos from the Springfield robbery.

The fourth heist, at 43780 Parkhurst Plaza, Ashburn, came Nov. 4. In the previous three, the woman taped a note to a box and shoved it toward a teller. This time, Loudoun sheriff's deputies said, she opened a purse and showed a gun.

In an affidavit for a warrant to search Martinez's apartment in the Shenandoah Crossing complex, just off Route 50 near Chantilly High School, Fairfax Detective James A. Williams said the robber's note in the Springfield holdup "appeared to be computer generated."

Williams wrote that the woman stood in the lobby, chatting on the phone and holding a box while waiting for a teller. Six employees were working, and several customers were there at 3:30 p.m. that Saturday, according to Williams.

The woman remained on her phone as she approached the first available teller, Williams wrote, and placed her box on the counter. The detective said the note attached to the box read: "You have forty seconds to put all your money in the box. Do not make any sudden moves."

The suspect, apparently breaking from her conversation, then told the teller, "Put all 100s and 50 dollar bills in the box," Williams wrote. The teller did not meet the robber's efficiency standards, Williams wrote, sparking a complaint: "You're taking too long, you have forty seconds. I need you to empty all the drawers, you have three."

The teller complied, and the woman left the bank. Officials did not say how much has been stolen. A bank robbery expert said his experience indicated that it was probably $1,000 to $3,000 in each robbery.

Williams said in his affidavit that he met with someone who had seen footage Friday of the Ashburn holdup. The person, who was not identified, reportedly had a still photo of Martinez. The person was shown a still photo of the Ashburn robber and said it was Martinez, Williams wrote.

Another person, also not identified by police, went to the West Springfield police station after seeing Friday's news, Williams said. That person named Martinez as the suspect, Williams wrote, and provided the Chantilly address.

Police searched the apartment Saturday night, court records show. What they took could not be learned.

Neighbors said they did not know her. Managers at her complex said they had been told not to comment.

Kraig Troxell, a Loudoun County sheriff's spokesman, said Martinez had ties to New Mexico. Fairfax police said they doubted that she had been here long.

The stepmother, who said she did not wish to speak at length, said Candice Martinez grew up in Santa Fe and might have come to the Washington area to stay with a relative.

Troxell said Martinez should be considered "armed and dangerous" because she showed a gun in the most recent robbery.

The investigation was featured Saturday night on the TV show "America's Most Wanted."

Fairfax's computerized court records show that a woman with the same name and birthday (the year of birth was not listed) was issued a traffic ticket Oct. 4 for violating HOV rules. The $107 payment for the fine and court costs was received Thursday. It was unclear yesterday how payment was made.

Staff writer Martin Weil contributed to this article