A Queens man with a history of mental problems was arrested Saturday in the vicious slaying of a psychologist attacked in her office with a meat cleaver, police said. David Tarloff, 39, was taken into custody in the morning after investigators matched him with three palm prints found at the bloody crime scene, said Police Commissioner Raymond Kelly. Tarloff was questioned for about 20 minutes, and the interrogation stopped when he asked for a lawyer, police said. Murder and attempted murder charges were pending, Kelly said. It was not clear Saturday evening whether he had gotten a lawyer. Therapist Kathryn Faughey was slashed 15 times with the cleaver and 9-inch knife in her Manhattan office Tuesday evening. A psychiatrist who worked in the building, Dr. Kent Shinbach, went to Faughey's aid and was badly injured.