COLORADO SPRINGS, Colo. -- A Fort Carson soldier accused of sexually assaulting two teenagers and killing one of them now faces a charge of sexual exploitation of a child.

The new charge was filed Thursday against 21-year-old Spc. Robert Hull Marko.

Prosecutors said a DVD containing child pornography was found at Marko's home. It wasn't immediately clear if the new charge related to either of the other two cases against him.

Marko faces charges of first-degree murder, sexual assault, assault and kidnapping in the death of 19-year-old Judilianna "Judi" Lawrence on Oct. 13. According to El Paso County sheriff's investigators, Marko met Lawrence online, through his MySpace page. He's accused of taking her to a remote mountain area, sexually assaulting her and then slitting her throat.

He also faces charges in the sexual assault of a 14-year-old girl five days before Lawrence was killed. A preliminary hearing in that case is scheduled for April 23. The teen was a runaway from a psychiatric hospital.

On his MySpace page, Marko wrote, " I'm becomeing (sic) a cold hearted killer and can kill without mercy or reason,"

Marko was a mortarman in Charlie Company, 3rd Squadron, 61st Cavalry Regiment, 4th Brigade Combat Team of the 4th Infantry Division. He served a tour of duty in Iraq.

He's being held without bond in the El Paso County Jail and has a preliminary hearing set for April 23.