Police in Vermont are looking for possible victims of an accused pedophile who worked as a nanny in Pittsburgh and other cities across the United States.

"This is a very disturbing case in that he is a sexual predator who was actively seeking employment around children," said Detective Ben Katz, of the Vermont State Police.

Donald Shepherd, 23, a native of Zanesville, Ohio, is in custody in Vermont on charges of molesting a 10-year-old boy in his care.

Police are asking for help in finding other possible victims in the 19 cities in which Mr. Shepherd has worked as a nanny or at children's camps.

Authorities said Mr. Shepherd is a classic example of a traveling predator and likely has many victims.

Jeff Killeen, spokesman for the Pittsburgh FBI, said the Crimes Against Children Task Force here is helping police track Mr. Shepherd's history.

Police said he advertised his services on various nanny sites, including nannynetwork.com and eNannysource.com, and typically charged $350 a week. Detective Katz said Mr. Shepherd told him he worked in Pittsburgh last year or the year before but wasn't more specific.

Nannynetwork did not respond to a request for comment. A spokeswoman for eNannysource said the owner would not be available for comment until Monday.

Mr. Shepherd, who has been targeted by online pedophile vigilantes for at least three years, used numerous aliases and screen names on the nanny sites, including Douglas Shepherd, Jonathan Shepherd, Jonathan Fields and Parker Wilder.

The different names and frequent movement around the country have made him hard to track.

Mr. Shepherd, who had no prior record, was charged last week after he checked into a psychiatric ward and told doctors he was contemplating suicide because of his contact with the 10-year-old boy, police said.

He said he had not molested any of the children he had cared for in California, New York, Michigan and elsewhere.

Mr. Shepherd's family has told media outlets that he has long had an attraction to children. He was raised by his mother, but Detective Katz said he is estranged from his parents.

Police seized Mr. Shepherd's computer and other electronic devices and hope to build more evidence against him after a forensic search. He told Detective Katz that he has child porn on the computer. Police also hope to develop a better picture of his travels and employment history from the computer.

The case is being handled locally but could end up in federal court if police uncover victims in numerous states.

Police said Mr. Shepherd, told them he has worked or sought work there, in Pittsburgh and in these other cities: San Diego; Washington, D.C.; Atlantic Beach, Jacksonville and Orange Park, Fla.; Kingsland and Saint Marys, Ga.; Plainwell, Mich.; Elizabeth City, N.C.; Freehold, N.J.; New York City; Cincinnati and Springdale, Ohio; Galveston, Texas; Draper, Utah; and Oak Harbor and Coupeville, Wash.