Last month, the naked body of Jarrae Nykkole Estepp, 21, was found on the conveyor belt of an Anaheim trash sorting facility. The young woman had arrived in California from Oklahoma shortly before her murder.

Estepp was known to have been involved in prostitution. Between January and March 2012, she was arrested at least three times for prostitution, and in those cases, she was convicted three times of offering to engage in prostitution and once of engaging in an act of lewdness.

When she moved to California, police say she frequented an area known for prostitution. Only a short time later, her choice of activities would lead to her being the target of two suspected serial killers.

Santa Ana police had been investigating the disappearance of three suspected prostitutes since last fall. With the discovery of Estepp's  body in Anaheim, they finally got a break in the case.

Police were able to connect two registered sex offenders to the woman's death, in part because the men were wearing court-ordered GPS ankle monitors when they allegedly raped and murdered the woman. 

Steven Dean "Skeeter" Gordon, 46, and Franc Cano, 27, are registered sex offenders who were transients living in cars and an RV. In separate cases, Gordon and Cano were convicted of Lewd or Lascivious Acts with a Child Under 14. Gordon was convicted in 1992 and Cano was convicted in 2008.

Both men were ordered to wear GPS ankle monitors as a condition of parole. However, in 2012, both men cut off their ankle bracelets and fled to Las Vegas where they lived in the Circus Circus hotel and casino for two weeks until their capture.

After subsequent felony convictions for their failure to register, the men were again released from prison. They were ordered to check in with law enforcement every 30 days and again required to wear a GPS monitor. Additionally, they were ordered to provide DNA samples to a federal database and to have their computers monitored by federal agents.

Despite frequent contact with law enforcement, monitoring by federal agents, and wearing devices intended to monitor their whereabouts at all times, investigators believe the men were able to rape and murder four women in Oklahoma. They have been charged with four counts of rape and four counts of murder, and they are being held without bail until a May 19 hearing.

Investigators strongly suspect that the men were involved in the  murder of a fifth woman. They believe that, due to the transient nature of the men, the pair could be responsible for many more murders across the country. They say they are in contact with missing persons departments across the nation.

Sex offenders are typically at low risk of re-offense. Some, however, continue to commit crimes regardless of the restrictions placed on them.

In February, a sex offender went missing for a week after cutting off his ankle monitor and fleeing a Denver halfway house. Eric Eugene Hartwell, a twice-convicted sex offender, convicted of the rape of a 6-year-old girl and the attempted rape of a 17-year-old girl. He had numerous convictions for failure to register as a sex offender, was under federal supervision, and had previously cut off an ankle monitor in Washington and fled to Texas in 2009.