On June 29, 1993, a 46-year-old insurance broker named Markham Duff-Smith was executed in Texas using lethal injection. He was responsible for the murders of four individuals: Gertrude Duff-Smith Zabolio, Diana Wanstrath, John, and Kevin. Gertrude was Markham’s adoptive mother while Diana was his adoptive sister. Furthermore, John was Diana’s husband and Kevin was Diana and John’s son.
Markham Duff-Smith had the urge to live a lavish lifestyle, and this led to him getting rid of the Wanstrath Family. According to Murderpedia, after Gertrude Duff-Smith Zabolio’s death, his adoptive son was going to inherit $100,000 from her estate. Markham Duff-Smith’s plan even included the termination of Gertrude’s husband, Dow Zabolio. However, at the time of the incident, he was in Austria.
This terrifying case will be covered in detail in the upcoming episode of Prosecuting Evil With Kelly Siegler, which will air on Saturday, December 16, at 8 p.m. ET on Oxygen. This episode is titled, “The Cop Who Wouldn’t Stop”.
The official synopsis of “The Cop Who Wouldn’t Stop” reads,
“In an exclusive Houston neighborhood, an entire family is found dead of an apparent murder-suicide; Sgt. Johnny Bonds takes on the entire justice system to uncover the shocking truth and expose an underworld of murder for hire.”
What was Markham Duff-Smith’s last statement?
According to Find a Grave, Markham Duff-Smith’s last statement was,
“I am the sinner of all sinners. I was responsible for the ’75 and ’79 cases. My trial was not just; it was not fair; they lied against me. I love all of those on Death Row, and I will always hold them in my hands. Those who stood by me, I will always love you. Jim and Judy Peterson and Chaplain Lopez, I thank you for staying by my side.”
Apart from Markham, other people involved in this infamous case were: an ex-convict, Allen Janecka, Walt Waldhauser, and Paul MacDonald. Furthermore, Janecka was executed by lethal injection on 24 July 2003.
