A suburban Kansas City woman pleaded guilty Monday to killing a woman whose sexual torture and suffocation were videotaped.

In a deal with prosecutors that allowed her to avoid the death penalty, Dena Riley, 42, pleaded guilty to first-degree murder in the May 2006 death of Marsha Spicer, who was suffocated during sex at an Independence apartment that Riley shared with her boyfriend.

Riley also pleaded guilty to kidnapping, sodomy and sex abuse in the videotaped attack on Spicer, 41, of Independence, and to kidnapping, sodomy, sex abuse and assault in a separate videotaped attack on Michelle Huff-Ricci, 36, of Kansas City. Riley sobbed throughout the hearing as she answered each question from the judge, prosecutor and defense attorney with a simple "yes" or "no."

Huff-Ricci's remains were found in nearby Clay County, where Riley and her boyfriend, Richard Davis, are charged with capital murder.

As part of the deal, Riley was sentenced to life without parole for the murder charge and to eight additional life sentences and 239 years in prison for 25 other counts. She also agreed to plead guilty in Kansas on a federal charge of kidnapping a 5-year-old girl related to Davis after fleeing the Kansas City area in May 2006. Court documents said the girl had injuries consistent with sexual abuse.

Earlier this year, Davis was convicted and sentenced to death for Spicer's slaying. He also is charged in the federal case.

During Davis' weeklong trial in July, the key evidence was videotapes that prosecutors say Davis and Riley made to fulfill Davis' violent sexual fantasies. Jurors watched graphic DVD recordings taken from those tapes, one of which showed Spicer's death.

Huff-Ricci's death came to light after Davis and Riley were captured in southwest Missouri following a five-day manhunt and brought back to the Kansas City area, where they were charged in Spicer's death. Police have said both defendants led investigators to Huff-Ricci's remains near the Kansas City suburb of Liberty. Prosecutors believe Huff-Ricci was sexually assaulted at the couple's apartment in April 2006, then driven to Clay County and strangled there.