BATES CITY, Mo. – Police have taken a Missouri couple wanted in a grisly videotaped rape and murder into custody, officials confirm.

According to officials, the couple had a 5-year-old girl with them when they turned themselves in to authorities.

The FBI’s “most wanted couple in America,” Richard Davis, 41, and Dena Riley, 39, [pictured] called the highway patrol and turned themselves in Thursday because they were reportedly tired of being on the lam from charges that they sexually assaulted, beat and strangled 41-year-old Marsha Spicer and buried her in a shallow grave in a rural area in Bates City, Mo.

Police found a videotape of the activities leading up to Spicer’s death, and her actual murder, in the couple’s apartment. The couple had been on the run since May 19, when police discovered the tape.

“We’ve had some pretty heinous crimes around here, but nothing of this particular nature,” FBI Special Agent Jeff Lanza told FOX News.

According to Lanza, the couple had a 5-year-old girl with them when they turned themselves in. Lanza said federal investigators believe the girl was taken across state lines.

“We believe this girl was taken from her home in Pittsburg, Kan., and the FBI is investigating this as a kidnapping case,” he told The Associated Press in a telephone interview.

Pittsburg is in southeast Kansas, about 17 miles from Lamar.

Lanza said authorities were trying to determine any possible relationship between the girl and the couple. He also said authorities would try to determine whether she was a victim of a sex crime.

Davis and Riley are each charged with first-degree murder, first-degree assault, kidnapping, forcible rape and two counts of forcible sodomy.

Spicer had no idea what the couple was capable of, according to the victim’s older sister, Jackie Schumacher.

“I want them to remember every day of their life what they’re doing to all these people,” Schumacher said. “People don’t deserve this … people don’t deserve what they did.”

Kansas City resident Sherry Ballew fears that her daughter might also have fallen victim to the pair after seeing a still picture taken from the videotape of who she says is her daughter, Michelle Ricci. Ballew hasn’t seen her 36-year-old daughter since a few days after Ricci met Davis and Riley.

The wanted couple was sighted Sunday in Perryville, Mo., at the Hilltop Apartment Complex.

The Missouri State Highway Patrol interviewed a woman at the complex, Susan Summers, about the couple’s disappearance on Sunday. Police later learned the couple had been hiding in the back room of Summers’ apartment at the Perryville complex and escaped after officers left. Summers has been charged with two counts of hindering prosecution.

The Kansas City Star reported Thursday that the couple worked at a Kansas City fabricating business. Davis worked as a janitor and Riley worked part-time in light assembly.

Spicer is survived by two children and two grandchildren.