Texas Cold Case: Arrest in 1980 Murder After DNA Match Made

July 24, 2012— -- Nearly thirty-two years after Mildred McKinney was sexually assaulted, beaten and strangled in her home, authorities in Texas have made an arrest in the elderly woman's murder.

Authorities announced today that Stephen Alan Thomas, 53, is being held at Williamson County Jail on a capital murder charge for the Nov. 4, 1980 murder of McKinney, who was then 73.

Henry Lee Lucas, a convicted serial killer who has since died, had confessed to the crime, but his admission was discounted in the late 1980s after DNA testing, said Sgt. John Foster of the Williamson County Sheriff's Office.

"We never did know Stephen Alan Thomas until the DNA hit," Foster said. "That just opened a whole direction in the case."

Thomas' DNA was found on a ligature, which was used to tie McKinney's body, Foster said. His fingerprint was also found in her home, according to police.

On June 27, 2012, a lab test showed the DNA was a match.

Authorities traveled to Dallas to interview Thomas and later to Austin, where he had relocated to his parents' home, Foster said.

"The first time I talked to him, he denied everything and ever knowing Mildred McKinney, ever being in her house and any type of sexual contact with her," Foster said. "[If that was the case] his DNA being in that house should have never been in there. He kind of worked himself into a bit of a problem there."

Foster said that because of the pending investigation, he was unable to discuss any theories as to why McKinney was targeted or whether Thomas knew her. But he said he was "thrilled" to see an arrest after several decades.

"I've been an officer for almost 20 years and this was the worst homicide that I've ever seen. From looking at pictures and having this case for almost eight years now, this is just total brutality for this poor little woman."

McKinney's grandson, Bob Stapleton, released a statement to ABC News' affiliate KVUE praising the work of Foster and the Williams County Sheriff's Department.

"Without their resolve, their determination, and their passion for this cold case we may have never known closure to my grandmother's story. She was a glorious woman who my family and I love and cherish and who will continue to live on in our fondest memories," he wrote.

Thomas is being held at Williamson County Jail on a $1 million bond.