1979 Cold Case Solved: Texas Girl Killed By Man Who Was Already Executed for Another Murder

Last week, 12-year-old Lesia Mitchell Jackson's murder case was officially closed by police -- 42 years after the young girl's body was found on September 13, 1979.

The girl disappeared a week earlier, after spending the day at her neighborhood pool. Her glasses were found the next day, but it wasn't until the 13th that an oilfield worker found her body in what police called "a heavily wooded area." Jackson had been sexually assaulted and killed and, despite "an extensive investigation into her death that lasted for years," the case went cold.

A new division at the Montgomery County Sheriff's Office, dubbed the Cold Case Homicide Squad, took over the investigation in 2005 -- but it would still be another 16 years until a forensic technology called M-Vac was used to process evidence from the girl's clothing in 2021. The M-Vac is a wet vacuum which "loosens" and captures DNA material from "porous areas that are difficult, if not impossible, to reach otherwise."

That DNA was then used to create a profile of Jackson's killer in April 2022, which was uploaded to the FBI. A match was then found in their system for a man named Gerald Dewight Casey. A blood sample from Casey retrieved back in 1989 was later confirmed as a DNA match from the M-Vac evidence and, on July 8, 2022, he was confirmed as her murderer by authorities.

Casey, it turned out, had already been executed 20 years earlier -- dying by lethal injection on April 18, 2002 for another Montgomery County murder from 1989.

According to KHOU, Casey and an accomplice planned to steal a cache of guns from a man named Daryl Pennington while he was at work at the time. When they got to the man's home, however, a woman named Sonya Lynn Howell was at the residence. She was reportedly shot nine times and her body was dumped in the woods nearby. Casey was convicted of her murder in 1991.

"The tenacity and diligence in solving this case by a dedicated team is a reminder to our public and to those who commit crimes in our communities that we will never cease our efforts to solve the hardest of cases and bring closure to traumatized families," said the Montgomery County Sheriff's Office in a statement.

The department added that they will "continue to explore future advances in technology that can assist us in solving other cases currently under investigation."