David Albert Dowler was born in 1953 in Albuquerque, New Mexico, to a U.S. Air Force colonel and his Japanese wife. He was described as a caring and intelligent individual, participating in wrestling and karate during his high school years. Dowler had a keen interest in electronics and ham radio, even assisting emergency services during a riot that disrupted communication lines.

After high school, he attended the University of New Mexico, studying electrical engineering, physics, chemistry, and mathematics, but did not graduate. In 1976, he married Janet, and the couple had two daughters. They relocated to Midland, Texas, in the early 1980s, where Dowler worked as a sales representative for Daniel Industries. He later co-founded a photo processing business in Odessa with Juan Antonio Casillas.

Between 1983 and 1987, Dowler poisoned three acquaintances in Odessa, Texas. His first known victim was 26-year-old Lisa Blythe Krieg, found dead on August 16, 1983. Dowler claimed she had committed suicide using cyanide he provided, and he cleaned her body to make the death appear natural. He also alleged involvement in secret government operations, asserting that he protected Krieg from assassins.

On February 12, 1986, Dowler's business partner, Juan Antonio Casillas, was found dead with cyanide in his system. Dowler had previously expressed concerns about Casillas' well-being to mutual acquaintances.

The final known victim, 29-year-old Leza Chandler, was discovered dead on June 29, 1987, from acute chloroform poisoning. Dowler had a history of providing chloroform to friends for recreational use and claimed to have had a premonition about Chandler's death. He was arrested on August 20, 1987, after a search of his residence revealed chloroform bottles, a .22-caliber pistol, and two homemade silencers.

Dowler was convicted of Chandler's murder on January 28, 1988, and sentenced to life imprisonment. He remains incarcerated at the Clements Unit in Amarillo, Texas.