Erin Corwin's body was found 100 feet down a mine shaft in a remote area of the high desert near Joshua Tree National Park after a nearly two-month search.

SAN BERNARDINO, Calif. (KABC) -- A former Marine on Tuesday was sentenced to life in prison without parole for the 2014 murder of a 19-year-old pregnant woman with whom he was having an affair.Earlier this month, Christopher Brandon Lee, 27, was found guilty of first-degree murder in the killing of Erin Corwin, whose body was found in an abandoned mine shaft outside Twentynine Palms on Aug. 16, 2014.Lee had admitted to strangling Corwin, the wife of another U.S. Marine, and pushing her head-first down the mine shaft in the middle of the desert in June 2014.Lee initially pleaded not guilty to killing the woman, whose husband was stationed with Lee at the Twentynine Palms Marine Corps base.Friends told investigators that Corwin believed she was pregnant and that Lee might be the father. However, Lee said he didn't kill Corwin because of the pregnancy situation, but because Corwin confessed near the mine shaft to molesting his daughter."I made the decision to kill her," Lee testified in court Nov. 4. "I was controlled by the anger. The hate I felt that day. It was something I never want to experience again."Lee had told Corwin he was taking her out to the desert near Joshua Tree National Park for a surprise. According to the woman's friends, she thought Lee might be planning to propose to her.Lee said he approached Corwin from behind and strangled her for at least five minutes with a garrote made up of two pieces of rebar and a cord. He said he then dragged Corwin's body to the mine shaft, pushed her inside and ignited the space."When a family loses someone so senselessly, every little thing takes on a new meaning," DeeAnna Heavilin, the victim's sister-in-law, said at the sentencing. "I'll never be able to hear the words 'strangle,' 'propane,' 'rebar' or 'mine' without being brought back into the hell that we've been thrust into for the past two years."During the trial, when prosecutor Sean Daugherty asked the 27-year-old Lee if he was the person who strangled Corwin, he replied, "Yes, I am."For nearly two months people searched for Corwin and prosecutors said Lee told detectives he had no idea where she was."I was afraid to tell the truth and thinking I could get away with it. I was still really angry at the time, I didn't want anyone to find her then," Lee said. "I'm not angry anymore and I'm no longer scared to tell the truth. This is something that I have to do. I have to let everyone know what I did and accept the punishment that they give me for it."Corwin's body was found hidden 100 feet down the mine shaft in a remote area of the high desert. She had disappeared in June 2014."I took the stand to tell the truth," Lee said in court Tuesday. "I did this knowing that because I took your daughter in an act of rage."In an interview, San Bernardino County Deputy District Attorney Sean Daugherty described the killer's statement as "nonsense.""It's what he does -- he crafts lies around the facts of the case," Daugherty added.Corwin's mother, Lore Heavilin, also read a statement in court."I cannot understand why anyone would think murder is OK, how that would get rid of your problems," she said. "All Chris had to do was move to Alaska and change his phone number."