Videotapes made by a couple accused of raping and strangling one woman and sexually torturing another gave authorities an unprecedented level of evidence, the Jackson County prosecutor said Wednesday in announcing new charges against the female defendant.

Dena D. Riley, 40, now faces 26 counts listed in an indictment unsealed during a brief arraignment where she sat silently as her public defender entered not guilty pleas on her behalf.

Riley and Richard D. Davis, 42, initially were charged with six counts each — including first-degree murder — in the May 14 sexual torture and strangulation of 41-year-old Marsha Spicer. The charges were based on a videotape found in the couple's Independence apartment.

Both now also are charged with the April 8 videotaped sexual assault of Michelle Ricci, 36. A 40-count indictment against Davis was unsealed last week.

Ricci's charred remains were discovered in a rural area of neighboring Clay County after Davis and Riley were captured in late May and gave statements to investigators.

Any charges in Ricci's death would be filed in Clay County because authorities believe she was driven there and killed after the alleged assault in Independence. No such charges had been filed there as of Wednesday.

The homemade videotapes showing Spicer and Ricci being sexually tormented by Davis and Riley amount to "a level of evidence that's pretty unprecedented for criminal prosecutions," Jackson County Prosecutor Mike Sanders said Wednesday.

"If you look at cases around the country and around the world, it's incredibly rare to have a crime allegedly committed on tape," Sanders said. "A violent crime allegedly committed on tape makes it even rarer. But beyond that to have it voluntarily taped puts it in, I think, the rarest category."

The 26 counts against Riley include seven involving Spicer and 19 involving Ricci. Davis is charged with 16 counts involving Spicer and 24 involving Ricci.

Sanders said the video of Ricci being brutalized is longer than the tape of Spicer, leading to the higher number of charges in the Ricci case.

Davis faces more charges than Riley because, Sanders said, there are more scenes of him on the tapes. But both defendants appear equally involved, he said.

"There is no line, we think, between one person being more culpable or being the leader versus the other," Sanders said.

Riley and Davis also have been indicted in Kansas on a federal charge of kidnapping a 5-year-old southeast Kansas girl related to Davis after fleeing the Kansas City area.

The girl was with the couple when they were captured May 25 in southwest Missouri. Court documents said the child had injuries consistent with sexual abuse.

Sanders expects to decide soon on whether to seek the death penalty against Riley and Davis — before Riley's next court appearance on Sept. 22, but after the Aug. 8 primary election in which Sanders is a candidate for Jackson County executive.