Homicide detectives in South-Central Los Angeles usually do not wait long for a murder. So on Friday night, during Detective Marcella Winn's first weekend on call, she spends an edgy evening at home, waiting for the call of death. She watches a video of the movie "Tombstone" and munches on popcorn, but she can not keep her mind on the plot. She keeps waiting for the phone to ring. Winn has only been in the homicide bureau two weeks, and this will be her first murder investigation. She would just as soon get started tonight. But this is a rainy spring night, one of the rare Friday nights in South-Central when people are not being battered, bludgeoned, knifed or shot to death.

On Saturday morning, she cancels her pedicure appointment. She is afraid of having to race to a murder scene with wet toenail polish. She spends a few hours watching reruns on television, but it is impossible to relax. Waiting for a homicide call is like waiting for a big sneeze that just won't come.

When the sun goes down, Winn is sure that tonight is the night. After all, this is Saturday night, the most murderous night of the week. And there is a full moon, which usually kicks the pace of mayhem and murder on the streets into another gear. At 9 p.m., she turns in, hoping to catch at least a few hours sleep. She tosses and turns, waking up every hour or two to check her answering machine and her beeper to make sure she has not slept through a call.

By Sunday morning, Winn is a wreck. She buys a paper and discovers that people were murdered all over the city this weekend. Just not in South-Central. All that worry for nothing. She dozes off at about 11.

It seems to Winn that she just closed her eyes when her telephone finally rings. She checks her alarm clock. It is a few minutes before midnight. "This is it," she says to herself. "No one else would call this late."

"You got one," the night supervisor tells her. "Male Hispanic. Shot in the chest. On the street. Two possible witnesses. Forty-ninth and Figueroa."

*

Winn meets Detective Pete "Raz" Razanskas, who is waiting at the Southeast Division parking lot in an unmarked squad car, engine running. They are partners, but for a while, it will be an unequal partnership. He will play the role of mentor and teach Winn the rudiments of a murder investigation. Razanskas (pronounced ra-ZAN-skus) is a supervising detective at South Bureau Homicide. The bureau is responsible for all murder investigations in Los Angeles' killing fields, a jagged strip of streets that runs from South Los Angeles to the harbor. This is such murderous terrain that if it were a separate city, it would rank among the nation's top 10 for homicides. Winn and Razanskas work a section of South Bureau centered in South-Central.