Shortly after a Tuesday news conference at which police asked for the public's help in finding a missing Upper East Side woman, detectives received a call from a tipster who claimed the woman had been shopping in the Hamptons.

Friday, sources said, detectives scratched that possibility off the list. Sources said detectives visited the Bridgehampton market in question, reviewed its security surveillance tape and determined that the caller had been mistaken.

Lacking any hard evidence, detectives continued to work under the assumption that the woman, Svetlana Aronov, 44, was abducted, probably by someone she knew.

Still, they left no possibility unexplored, checking databases to see which ex-convicts, particularly sex offenders, live or work near Aronov's York Avenue co-op.

At about 2:30 p.m. Monday, Aronov left the home she shares with her oncologist husband, Alexander, 45, and daughter, 9 (the couple also has a 22-year-old daughter) to walk Bim, her father's cocker spaniel.

She never returned, leaving behind her wallet and the dinner she had started preparing - signs, detectives believe, that she is the victim of foul play.

Detectives have interviewed a man who visited the Aronovs' building about three hours before she was last seen. He is not considered a suspect, though it wasn't immediately clear what relationship he might have to either Aronov or her husband.

In an unrelated case, police said they are looking for Maria Foster, 31, of the Bronx, who was last seen Feb. 13 when she left her home with a friend to clean someone's house.

Her fiance, Keith Walton, reported her missing on Thursday, though it wasn't clear why there was a delay in doing so.

Police said neither Foster nor Walton has a criminal record, and there is no history of domestic violence between them.