A man who worked for a dog-walking service was found guilty of animal cruelty yesterday for tossing a client's pet to its death from a ninth-floor balcony in Arlington County.

Paul M. Kramer, 32, described by his attorney as mentally retarded, faces up to a year in jail and a fine of up to $2,500 for throwing a lapdog named Holly from a couple's high-rise apartment on Sept. 3. Kramer said the incident was an accident.

Tears and angry outbursts followed the trial, whose main witness was a 13-year-old girl who testified she saw a struggle involving a person and a dog from a park across the street from The Williamsburg apartment building. The girl said she saw the person using both hands to hold the animal by its midsection, dangling it over the balcony rail and letting it drop.

Kramer, who walked dogs for Always There Pet Care LLC, testified that the dog bolted from him when he opened the apartment and ran onto a balcony through a door that had been left open. As he tried to calm the dog, he said, the animal bounded onto furniture and leaped the balcony rail.

General District Court Judge Thomas Kelley Jr. found Kramer guilty of a Class 1 misdemeanor after a three-hour trial. He declined to pass sentence yesterday and ordered Kramer to undergo a presentencing evaluation.

Mayuri Sobti, who had testified that the dog had been like a child to her and her husband, wept upon hearing the verdict. Afterward, as her husband, Brett Walter, consoled her, Rick Luckett, a caseworker with the Arlington Community Services Board who worked with Kramer, confronted Sobti in the courtroom, saying: "I hope you're glad you ruined someone's life."

Outside the courtroom, Kramer, also in tears after the trial, declined to comment. Michele Fisher, an owner of the dog-walking service, said her firm would probably have to let Kramer go because of the conviction, although she said she still did not believe that Kramer had intentionally harmed the animal.

Assistant Commonwealth's Attorney Alejandra Rueda Hammack argued in court that Kramer had given inconsistent accounts of what happened, while the girl was certain of what she had witnessed. Holly's damaged metal tags, found on the couple's balcony, also suggested that a fierce struggle had taken place on the balcony, Hammack said.

Another witness testified that she had been sitting near the pool when she heard a struggle between and man and a dog, including a man cursing. Then the animal's body landed near her.

Defense attorney William D. Pickett challenged the girl's account. And he presented character witnesses who testified about Kramer's devotion to animals. Sentencing was set for April 1.