SAN BERNARDINO, Calif. (KABC) -- A former U.S. Marine confessed in San Bernardino County Superior Court to killing his pregnant lover, who was the wife of another Marine, back in 2014.Christopher Brandon Lee was a Marine serving on the base at Twentynine Palms back in the summer of 2014.Even though he was married, he was having an affair with Erin Corwin, the wife of a fellow Marine.Corwin had just informed Lee she was pregnant, which prosecutors said left him in a difficult position."You had a girlfriend who was pregnant right?" the prosecutor questioned."Yes," Lee answered."And you had a wife who was expecting to go back to Alaska in just a few days," the prosecutor asked."I did," Lee said.Prosecutors said Lee took Corwin out to an abandoned mine shaft, in the middle of the desert near Joshua Tree National Park, and killed her."You're the one who killed her?" the prosecutor asked."Yes I am," Lee answered."You're the one who strangled her to death?" the prosecutor questioned."Yes I did," Lee said.Lee said he approached strangled Corwin with a garrote made up of two pieces of rebar and a cord.In a new accusation, Lee said he didn't kill Corwin because of the pregnancy situation, but because Corwin confessed out near the mine shaft to molesting one of his family members."What was on your mind?" the prosecutor asked."Just hate, that's all it was, I had loved her, and every bit of that love that I had was turned to hate," Lee responded.That's when Lee said he strangled Corwin with a garrote made up of two pieces of rebar and a cord. Lee then said he pushed Corwin down the mine shaft."What part of Erin entered the shaft first?" the prosecutor asked."She went in head first," Lee responded.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."Closing arguments are expected Wednesday morning. The case will then head to the jury.