OKLAHOMA CITY - Prosecutors in Tarrant County, Texas have charged an accused serial killer and rapist with the murder of Oklahoma teenager Casey Jo Pipestem.

Investigators say the killer is likely responsible for more than a dozen deaths at truck stops across the country. State and Federal agents say many of the slayings happened in Oklahoma.

Pipestem's family has waited nearly a decade for John Robert Williams to be charged. Williams is quickly becoming known as the "Big Rig Killer." Williams is already serving life sentence plus 20 years in a Mississppi prison for another murder. He is implicated in as many as 14 cases, and he now has a fresh charge for the murder of Casey Jo Pipestem.

"She was beaten, raped, strangled and thrown off a 37-foot bridge naked," Pipestem's older sister Taffney Harjo said.

Family members say Pipestem was lured into Williams' truck by his girlfriend accomplice, Rachel Cumberland. Then, police say, Pipestem's body was found 200 miles away in Grapevine, Texas.

"[The truck drivers] take their crime scene with them," Terri Turner with the Oklahoma State Bureau of Investigation said. "They live in that truck and they can be in three different states in one day."

Turner is the one who put the puzzle pieces together. She investigated seven truck stop slayings and found a pattern.

"Over the next four months, consecutively, there were four more girls that were found," Turner said. "As we began to identify the victims, we found that they were prostitutes who worked out of truck stops."

Pipestem was the last of Turner's initial cases and the beginning of an FBI investigation into truck stop killings nationwide. The investigation is work Turner says she is proud of and something she hopes will continue to find justice and give family members closure.

"Even though it was nine years ago, it's an everyday process that I have to fight every morning so I can go on with my day," Harjo said.

Cumberland is also behind bars in Mississippi. It is unclear if Texas prosecutors plan on charging her in connection with Pipestem's death. An official with the Tarrant County District Attorney's Office says a trial for Williams in Texas will only take place if he is released from prison in Mississippi.