Pamela McDonald went missing on April 2, 2009, 13 and a half years later her case has still not been solved.

According to the Midland Reporter-Telegram, soon after 39-year-old McDonald went missing, her silver Lincoln Towncar was found near Monahans in a rest area parking lot around mile marker 70 on I-20.

Texas Rangers determined after an investigation that her vehicle had been at the rest area since April 4, 2009.

In January 2012, Upton County Sheriff's Office was called to an oilfield location north of Rankin where human remains had been discovered. It was later determined by forensic anthropology that the remains were that of Pamela McDonald.

Texas Department of Public Safety featured her story on an episode of their YouTube series "Cold Case Investigation: West Texas Region" you can check it out below.

Pamela McDonald was a mother of three and was last seen at 1 a.m. on April 2 when she told her family she was going out for one last drive in her silver Lincoln Towncar before it was repossessed the following day.

Her oldest daughter reported that the stay-at-home mom would often go out on late-night drives once her elementary-aged children would go to bed but it was unlike her not to return within an hour or so.

The family had fallen on tough times in the months prior to her disappearance but authorities reported when her car was found in Ward County days later, it was locked with no keys inside or within the vicinity of the vehicle and no mechanical issues were discovered.

No activity on her cell phone was observed in the hours around her disappearance and McDonald was reportedly not on any medications that might have caused the disappearance.

Her husband Charles McDonald is the only suspect in the investigation but no arrests have been made.

If you have any information on the disappearance of Pamela McDonald, you are asked to contact the Texas Rangers at 1-800-346-3243.

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