For more on this story, read the coverage from CNN affiliate WRAL.
(CNN) -- Former U.S. Marine Cesar Laurean was convicted in North Carolina on Monday of first degree murder in the 2007 death of Lance Cpl. Maria Lauterbach, who was eight months pregnant when she died.
An autopsy showed that Lauterbach, 20, died of blunt force trauma to the head. Police unearthed her charred body from beneath a barbecue pit in Laurean's backyard in January 2008. She had disappeared the month before.
Laurean, who was dressed in black slacks and wore a white shirt and black tie, did not show any emotion as the judge read his sentence of life in prison without parole. He either said or mouthed something to someone in the audience of the courtroom before he was led out in handcuffs, video showed.
Laurean and Lauterbach were stationed together at Camp Lejeune, North Carolina.
"I truly believe that Maria was the perfect victim. Because of her credibility problems, our pleas for help [after her disappearance] were rejected or discounted by everyone," Mary Lauterbach, the victim's mother, said after the verdict was read, CNN affiliate WRAL reported.
North Carolina prosecutors alleged Laurean killed Lauterbach on December 14 and used her ATM card 10 days later before fleeing to Mexico. Laurean was arrested there in April 2008. He holds dual citizenship in the United States and Mexico.
Before her death, Lauterbach told the Marines that Laurean had raped her. Laurean denied it, and disappeared just a few weeks before a scheduled rape hearing at Camp LeJeune. WRAL reported Lauterbach later recanted the allegation of rape.
The DNA of Lauterbach's unborn child did not match that of Laurean, according to law enforcement personnel.
Onslow County Chief Assistant District Attorney Ernie Lee said in his closing argument that Laurean needed to kill Lauterbach to salvage his military career, WRAL reported.
"I can get rid of my problem," Lee said to explain what Laurean might have been thinking, reported WRAL.
Authorities found Lauterbach's body after Laurean's wife, Christina, produced a note her husband had written claiming the 20-year-old woman slit her own throat during an argument, according to officials.
Although a gaping 4-inch wound was found on the left side of Lauterbach's neck, autopsy results indicated that the wound itself would not have been fatal and may have occurred after death.
"It is a just result, but still a tragedy with no winners," Merle Wilberding, a lawyer who represented the Lauterbach family, wrote in an e-mail to CNN after the verdict.
Laurean's lawyer said his client would appeal the decision.
CNN's Susan Candiotti contributed to this report.