OAKLAND (CBS SF) — An Oakland man convicted and later paroled in a 1994 killing pleaded guilty Thursday to two counts of murder for killing a 1-year-old boy in 2009 and then murdering the boy’s mother because she was a witness.

The unusual guilty pleas by Curtis Martin III, 41, during the jury selection phase of his trial in Alameda County Superior Court mean that he will serve a term of life in state prison without the possibility of parole.

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Prosecutor Tim Wellman said he has never known of a case in which a defendant pleaded guilty to charges that bring life in prison without parole.

Martin’s lawyer, Deborah Levy, said she believes Martin pleaded guilty because “he didn’t want to go through the publicity of a trial.”

Martin pleaded guilty to second-degree murder for killing 17-month-old Jashon Williams sometime between Oct. 25, 2009, and Nov. 8, 2009. Wellman said the killing most likely occurred on Oct. 31 or Nov. 1.

Authorities said that after Martin killed Jashon, he dumped the boy into the San Francisco Bay. His decomposed body was found on Nov. 15, 2009, in the Berkeley Marina.

Martin also pleaded guilty to first-degree murder for killing Jashon’s mother, 23-year-old Zoelina Toney, on Nov. 13, 2009, by shooting and bludgeoning her. Toney’s body was found in Aquatic Park, along the shoreline east of Interstate Highway 80 in Berkeley, about 4 a.m. that day.

In addition, Martin pleaded guilty to three special-circumstance murder allegations: murdering Toney because she was a witness to the murder of her son, lying in wait, and committing multiple murders.

Martin also admitted to having three prior felony convictions: a 1994 voluntary manslaughter conviction for the death of the 3-year-old son of his girlfriend at the time, a 1992 conviction for possession of an assault weapon and a 1988 conviction for first-degree robbery.

The Alameda County District Attorney’s Office decided before jury selection began not to seek the death penalty for Martin.

Wellman said Martin “pleaded guilty as charged” and didn’t gain anything from his pleas.

He said it would have been difficult to get a first-degree murder conviction for Martin for Jashon’s death because his body was so badly decomposed that no cause of death could be determined, even though two autopsies were conducted.

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Wellman said Martin and Toney were dating but lived separately in nearby residences. He said Martin took physical custody of Jashon even though he wasn’t the boy’s biological father, and Toney became suspicious after she hadn’t seen Jashon for several weeks.

“She wanted her child back and told Martin she would report him to the police” if he didn’t return the boy, Wellman said.

Martin has now been convicted of killing three people.

In the earlier case, he was charged with murder for the Feb. 11, 1994, death of 3-year-old Devin Brewer, who was the son of his girlfriend.

The probable cause statement said the boy died of blunt force trauma to the head, and his mother reported that he had suffered several burns and blunt force injuries in the weeks prior to his death.

However, the Alameda County District Attorney’s Office agreed to a plea deal that called for Martin to plead no contest to the lesser charge of voluntary manslaughter and be sentenced to 11 years in state prison.

When he sentenced Martin on Jan. 9, 1995, Alameda County Superior Court Judge Larry Goodman expressed frustration at the plea agreement and the light sentence but said he was powerless to change it.

“The laws of this state have somehow tragically been ignored for the perpetrators of the most hideous crime, the killing of our most precious gift, our children,” Goodman said.

Martin was paroled from state prison on Sept. 7, 2000, after serving only about six years.

However, he had to return to state prison for three short stints for violating the terms of his parole.

Martin was scheduled to be sentenced by Superior Court Judge Vernon Nakahara on Dec. 3.

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