Three CBS television technicians who were slain when they tried to save a woman's life may have stumbled into the work of a professional hit man, police said yesterday.

Police said the assassin may have killed five persons in what started as an attempt to silence federal witnesses in an investigation of the disappearance of $5.5 million from a bankrupt diamond importing firm.

The body of Margaret Barbera, the woman police believe was resisting an attacker when the three CBS technicians walked into a midtown rooftop garage, was found yesterday in an alley behind a lower Manhattan office building. The three technicians who were slain Monday night were identified as Leo Kuranaki, 54, Robert Schulze, 58, and Edward Binford, 55.

Police said Barbera, 38, was the former comptroller of the Candor Diamond Corp., which has filed for bankruptcy. The FBI said she had been questioned in a federal embezzlement investigation.

The possible fifth victim, Jennie Soo Chin, 46, a Candor bookkeeper who also was questioned by federal agents, was reported missing last Jan. 25. On Jan. 24, detectives said, she visited Barbera in her apartment.

A few days later, Chin's car was recovered in the Bronx, police said, and a .22-caliber shell casing was found in the vehicle along with bloodstains. Laboratory technicians matched the shell casing in the car with shells found at the scene of the slaying of the CBS employes.

Police said the three men getting their cars on their way home from work apparently interrupted a "very efficient" killer as he was shooting Barbera, whose auto was also parked in the garage.

The gunman apparently concluded that the CBS employes had seen him shoot the woman. He pursued them across the rooftop garage, shooting them in the head before fleeing in a white van with Barbara's body.