In a release announcing a guilty plea in a 2008 killing, Dallas County District Attorney Michael Jackson said the defendant needed to “pack his suitcase because he is going to go off to prison for a long time.”

Monday, in front of Circuit Court Judge Marvin Wiggins, Rodriques Simpson pled guilty to manslaughter in the death of Shamika Walton.

Walton was reported missing on Nov. 21, 2008 by her mother. Following a series of interviews and investigation, authorities settled the last person to see Walton alive was her boyfriend, Simpson.

In an affidavit, Simpson’s cousin, Darnell Gee, told investigators Simpson had come to his home on Nov. 21 and said he had “killed his girlfriend Shamika Walton.” Gee said Simpson, who was driving a car owned by Walton, went as far to show him Walton’s body that was located in the trunk.

“According to Darnell, Shamika’s eye was open and she appeared to be dead,” the affidavit read.

Police reported Simpson then dumped the body in a “wooded area near where his mother was building a house.” Authorities checked the area and discovered Walton’s body.

During interviews with Simpson, he said he had been in an argument with Walton on Nov. 21 and that “he knocked her into a table or piece of furniture, he then punched her in the face.” Simpson then said he attempted to revive Walton but was unable to.

In the release from Jackson, Simpson reportedly had thought Walton was cheating on him, which lead to the fight.

Simpson, who reportedly served in the National Guard from Nov. 2004 to Nov. 2005, had claimed he was suffering from post-traumatic stress disorder from tours of duty in Iraq.

“He claims he had to put bodies in body bags during the war,” Jackson said, who added Simpson was diagnosed with PTSD in 2005 by Veterans Affairs.

In his plea, Simpson was sentenced to 20 years in prison by Wiggins.