By Alex Dobuzinskis

LOS ANGELES (Reuters) - A Los Angeles police officer was sentenced on Thursday to 16 months in jail for assaulting a handcuffed black woman who was complaining that she could not breathe and later died, prosecutors said.

Los Angeles Superior Court Judge Sam Ohta, in sentencing Officer Mary O'Callaghan, 50, suspended another 20 months of her jail term, meaning she will not have to serve that portion if she avoids violating her probation, prosecutors said.

O'Callaghan was charged with assault under color of authority but not with the subsequent death of 35-year-old Alesia Thomas, who was being arrested for child abandonment when she lost consciousness in the back of a police car in July 2012.

The coroner's office determined that acute cocaine intoxication played a major role in Thomas' death. Thomas had repeatedly complained to officers that she could not breathe.

A jury in June found O'Callaghan guilty of the charge, after viewing video from the car that showed the officer strike Thomas in the throat and shove her foot against the woman's groin, in between trying to secure a leg restraint on Thomas.

The trial followed a series of fatal police confrontations across the United States that sparked demonstrations and put law enforcement agencies under scrutiny over the use of force, particularly against minorities and the mentality ill.

An attorney for O'Callaghan, an 18-year police veteran who has served in the U.S. armed forces, had asked for probation and no jail time. She had faced a possible maximum sentence of three years in prison.

Prosecutors asked the judge to impose a six-month jail sentence, less than what the judge decided to hand down.

"We are keenly aware that a police officer's use of force should not be judged with 20-20 hindsight and that allowances must be made for applications of force in conditions that are rapidly unfolding and require split-second life or death judgments," prosecutors said in a written motion. "No such exigency existed in this case."

A police spokesman said O'Callaghan, who has been relieved of duty without pay, is still employed as an officer. He declined to immediately discuss any further details about possible discipline she may face.

"It should be clear to everyone that the LAPD and the criminal justice system will hold officers accountable for their actions when they operate outside the law," Los Angeles Police Chief Charlie Beck said in a statement.

(Reporting by Alex Dobuzinskis; Editing by Eric Beech)