SAN DIEGO -- An ex-con who ran down and killed a San Diego police motorcycle officer 19 months ago will be sentenced to life in prison without parole after pleading guilty to second-degree murder, a prosecutor said.

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ACCIDENT SCENE Man Accused Of Running Down Officer

Kevin Gerard Williams, 39, admitted Monday that he used a stolen flatbed truck to mow down Officer Terry Bennett in the line of duty on June 26, 2003.

Sentencing was set for March 14.

District Attorney Bonnie Dumanis had yet to decide if her office would have sought the death penalty against Williams if he had gone to trial and been convicted.

Last October, Williams -- diagnosed with schizophrenia and mild mental retardation -- pleaded not guilty and not guilty by reason of insanity.

Judge William Mudd ruled last year that Williams was mentally competent to stand trial.

The judge said the defendant had used his mental health deficiencies to secure "great benefit" to himself in his legal battles.

A number of doctors documented that Williams had exaggerated his symptoms over the years in order to get what he wants, prosecutor David Hendren said at an earlier court hearing.

In 2003, Williams was found incompetent to face trial and was sent to Patton State Hospital in San Bernardino County. After a short stay, doctors found that his mental condition had improved and he was returned to San Diego.

Williams -- whose mental capacity is estimated to be that of a 12-year-old -- had problems growing up that were exacerbated by homelessness and drug use, defense attorney Richard Gates said last year.

The day of the fatal crash, Bennett started chasing Williams in Encanto. The stolen GMC flatbed truck Williams was driving contained stolen tools and a generator, police said.

Williams made a hard U-turn and used the stolen truck as a battering ram to crush the officer into a fence, Hendren said.

He said Williams has a 30-year criminal history and had twice before led officers on chases.

The defendant had six prior felony convictions and has been to prison three times, prosecutors said. The defendant's latest stint in prison was for a 1997 robbery, for which he served 18 months, according to court records.