Authorities found what appeared to be bloodstains in two vehicles searched at the apartment of a suburban Kansas City couple accused of killing a woman whose sexual assault and torture was videotaped, according to court documents filed in the case.

The couple, Richard D. Davis, 41, and Dena D. Riley, 39, face charges of first-degree murder, first-degree assault, kidnapping, forcible rape and forcible sodomy in the death of 41-year-old Marsha Spicer. Spicer's naked body was found in a shallow grave on May 15 in Bates City, east of Kansas City.

Prosecutors have said a search warrant on the couple's Independence home found a videotape showing them beating, raping and choking Spicer.

The latest court documents say an investigator, looking in the garage, found a possibly bloodstained blanket in a Chevrolet S-10 pickup and what looked like a bloodstain in the upholstery of a 1993 Toyota Corolla.

A pitchfork was found in the Corolla's trunk.

In the apartment itself, the documents say, investigators found a marijuana cigarette, a bag of a leafy substance, a laptop computer, videotapes, a roll of duct tape and pieces of duct tape with hair stuck to it.

In the video, officials said, Spicer has duct tape around her wrists and over her eyes.

Investigators also tested the inside of a bathtub and took a bathroom sink's drain and filter.

Following eight days on the run, Davis and Riley were arrested in southwest Missouri on May 25 with a 5-year-old girl. Federal authorities are investigating possible kidnapping charges.

Investigators also are trying to determine if Davis and Riley are linked to a badly burned body found over the weekend east of the Kansas City suburb of Liberty. Jackson County Prosecutor Mike Sanders has said additional charges against the couple are likely and could include charges related to other slayings.

The Jackson County Coroner is examining the body, which officials said is so badly decomposed they couldn't determine gender.

Sherry Ballew has told Kansas City media outlets that she thinks the body belongs to her daughter, 36-year-old Michelle Ricci, who hasn't been seen since April 2 and was a friend of Spicer. A family member said police had asked both Ballew and a granddaughter to provide DNA samples.