COLORADO SPRINGS, Colo. -- An Army specialist accused in the slaying of a 19-year-old woman in El Paso County is due in court Monday.

Robert Hull Marko, 21, has been held without bond since his arrest in October. The Fort Carson soldier served in Iraq from January 2007 to February 2008.

Marko is accused of first-degree murder and sex assault in the death of Judilianna "Judi" Lawrence, who was reported missing in October. An arrest affidavit said the two met on the social networking Web site MySpace and that Marko led investigators to Lawrence's body off Old Stage Road. Her throat had been slashed and she had been raped, according to El Paso County Sheriff's investigators.

He also faces accusations that he raped a 14-year-old girl and sexually assaulted a third woman, according to an internal Army document obtained by the New York Times.

Five days before Lawrence was murdered, Marko is alleged to have picked up a 14-year-old girl after she fled from a psychiatric hospital. The girl claimed that a man matching Marko's description drove her to the mountains and raped her. Her description of the location "matches" the area where Lawrence was killed, according to the report in the Times. Marko is charged with two counts of sex assault on a child.

Marko is the sixth member of his brigade to be charged with murder in the U.S. Sen. Ken Salazar, (D) Colo., has requested an Army investigation into the Fort Carson soldiers who have been charged with murder.