Authorities continue to investigate the deaths of at least 12 prostitutes in three or more states. One victim was Casey Jo Pipestem, a member of the Seminole Nation of Oklahoma.

Authorities have divided the murders into two groups, believing they could be the work of two separate killers. Pipestem, 20, was thrown over a bridge after being beaten and raped.

Pipestem's body was found January 31 in Texas. Just a few days earlier, she had spoken with her sister, Taffney Harjo, in Oklahoma. Harjo said Pipestem promised to leave her life of prostitution.

Pipestem and some of the other prostitutes frequented truck stops. Pipestem was last seen at one in Oklahoma City.

Get the Story:
Sheriff doubts Leonard slaying linked to killings of six other prostitutes (The Shawnee News-Star 4/6)
Women of diverse backgrounds meet similar fates (AP 4/6)
Grit and luck weren't enough for Pipestem (AP 4/3)
Danger lurks in truck-stop prostitution (The Fort Worth Star Telegram 4/4)
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Stamping out prostitution nearly impossible (AP 4/4)

Related Stories:
Investigators in six states probe murders of women (02/27)
Authorities looking into murders of Indian women (2/17)
19-year-old Seminole woman beaten to death (02/05)