Dozens of detectives scoured the Upper East Side Wednesday collecting security tapes from buildings, handing out fliers and checking phone and financial records in the hopes of finding clues to what happened to the woman who disappeared while walking her father's dog on Monday.

Svetlana Aronov's husband tried to remain optimistic in the face of the grim reality that it has been almost three days since his wife vanished, and although police have come up with a plethora of theories, there is nothing solid to back any of their hypotheses.

"At first I was numb,'' Alexander Aronov, Svetlana's husband, said. "Now it's getting worse. I break down and cry often,'' said Aronov, 45, an internist who has offices in midtown and Sheepshead Bay.

Shortly after 2 p.m. Monday, Svetlana Aronov, 44, placed a plant she had been watering while her father was away near the front door of her York Avenue apartment. She put on a tan coat with a fur collar and white beret, grabbed her house keys and cellular phone then tromped out wearing fur-trimmed boots to take her father's black and white cocker spaniel, Bim, for a walk.

After the walk, she was going to JFK Airport to pick up her father, a semi-retired antiques dealer, who was expected to arrive on a flight from St. Petersburg, Russia at 5 p.m. Aronov had arranged for her mother-in-law to pick up her 9-year-old daughter from school. She told her mother-in-law she would leave an apartment key with the doorman so they could get in.

But Aronov and Bim never returned from their walk. Aronov's purse with her identification, credit and ATM cards was left inside the apartment. The plant and other objects she was going to take to her father were untouched. Her key was never left for her mother-in-law, and she never met her father at the airport.

Though his mother called him in his Brooklyn office around 3 p.m. when she couldn't get into the apartment, Alexander Aronov said he didn't get concerned until about 8 p.m. when he still hadn't heard from his wife.

That concern turned to worry when he arrived home around 10:30 p.m. to find his father-in-law waiting in the lobby and his wife's car in their parking garage. At that point, he said, he called 911.

Police used a bloodhound to track the scent of the cocker spaniel from the apartment near 63rd Street, up to 68th Street and York Avenue, where it ended abruptly.

Detectives are analyzing videotapes from businesses and apartment buildings along the five blocks it's believed Svetlana walked. Yesterday, a police van with the CrimeStoppers number, 800-577-TIPS roamed the neighborhood while a recording playing over a loudspeaker gave details of the incident and requested that tips be reported.

"I've been thinking every possible direction,'' said Alexander Aronov, who left Russia with his wife in 1982 and, after living in Italy and Canada, moved to New York in 1989. "Perhaps something recently or in her past, but I come up with zero. She's not the type of person to have enemies," he said of his wife of almost 25 years.

Police also delved into the background of Alexander Aronov, who the source said, was "extremely forthcoming" and found nothing suspicious.

Aronov said it was "logical" to suspect him. In fact, he said, "I suggested they investigate me" so they could clear him and concentrate elsewhere.

Svetlana helped run her husband's offices and dabbled in the importation of rare Russian books. Most involved in the investigation believe that if she was abducted, it was by someone she knew.

Aronov said the couple's 22-year-old daughter is "coping well" but their 9-year-old daughter has been sent to a friend's house for the time being. "The youngest, she knows her mom is missing but doesn't quite grasp it," he said.

As for himself, Aronov, sporting a couple days worth of stubble on his face, struggle to describe what he's feeling.

"It's not anger,'' he said. "I don't know what to be angry at. God? Life? Anger has to be focused. I'm very worried. I'm very, very worried."