Barbara Baylor's story sounded simple enough: She wanted to sell a flute to raise the down payment on a car for her teen-age daughter.

Steve Papier, owner of Wheaton Music Inc., looked at the expensive instrument, then at the polite, middle-aged woman with the hazel eyes, then at her daughter. After checking Baylor's Maryland driver's learner permit, Papier asked for her telephone number, saying he would decide later about the flute.

Baylor said she needed the money right away. Her next stop was around the corner at the Washington Music Center in Wheaton, where, with the help of a Tennessee driver's license, she introduced herself as Barbara Taylor, according to Chuck Levin, owner of the store.

Both Papier and Levin recognized the woman. Papier told police that two years before, calling herself Barbara Williams, she had purchased a flute from him and paid for it with a bad check. His files contained a photo of her taken in the store at the time she gave him the check, he said.

Levin and his wife, Marge, said the woman, accompanied by the daughter, had bought a flute and a piccolo from them two years before, also paying with a bad check.

"She was very pleasant and not the least bit nervous," recalled Marge Levin, of the woman's latest visit to her store.

When the woman offered a flute for sale to Levin in the recent incident, he paid for it with a $300 check, then immediately stopped payment.When the woman returned shortly thereafter, she spent about 45 minutes in the store, and accepted a check on another bank.

Both Levin and Papier telephoned Montgomery County police, who arrested the woman in the parking lot of the Central National Bank on Viers Mill Road in Wheaton, when she went there to cash Levin's second check. Papier said he saw her teen-age daughter walk away after the mother's arrest.

Montgomery County Police Detective Robert Bond said his department checked Federal Bureau of Investigation records and came up with 19 names for the woman -- 18 aliases and her real name, Barbara Billett. w

Warrants for the arrest of Billett and her husband, William Henry Billett, are outstanding in at least eight states, according to Lane Bonner, supervisory special agent for the FBI fugitive squad at the Baltimore field office.

"Every FBI field office in the continental United States was conducting an investigation to locate this individual because of her highly transient nature," he said. Bonner added that the FBI also sought Billett to interview her in connection with a 1979 bank robbery in Forest Lake, Minn.

In another Montgomery case two years ago, Billett paid for a flute and piccolo at Dale Music in Silver Spring with a bad check for more than $800, according to Carol Warden, instrument department manager at Dale Music.

The FBI's Bonner said local authorities around the country have reported that Barbara Billett's alledged method of operation was to move to a new community, enter her children in school under fictitious names, open a checking account with a small amount of cash after claiming she had lost her identification, get starter checks and start buying.

Bonner said Billett has four children: a son, 19, two daughters aged 6 and 11, and daughter Lore, 16, who accompanied her to the stores recently.

Billett's attorney, Robert Feeney of Gaithersburg, said the four children still are in the Gaithersburg area, and are receiving services including housing from local authorities. The 19-year-old son has a job, Feeney said.

The attorney said he does not know the whereabouts of William Billett.

Barbara Billett is being held on $50,000 bond and is scheduled to appear July 31 at a District Court hearing on three misdemeanor charges of passing bad checks stemming from incidents two years ago in Montgomery County.

Bond said that local authorities from jurisdictions in other states have placed "detainers" on Billett, which means that if she were released by Montgomery police for any reason, she then would be detained for another jurisdiction.

Bond said that when he went to the Billetts' Gaithersburg house a few days after Barbara's arrest, he found only the teen-age son and a rented piano.