Glennon Edward Engleman (1927–1999) was a St. Louis dentist who moonlighted as a hitman, concocting and carrying out at least seven murders for profit over the course of 30 years. He was already serving two life sentences in a Missouri jail when he pleaded guilty to the murder of a man and his parents in a separate contract killing. Engleman was a sociopath; he once stated that his talent was to kill without remorse and he enjoyed planning and carrying out killings and disposing of the remains, in order that it would net him financial rewards. Methods used to kill his victims included shooting, bludgeoning with a sledgehammer and car-bombing. Engleman died in prison of a diabetes-related condition in 1999. The exact number of his victims is unknown.
1958: Engleman is suspected of the death of James Bullock, 27, clerk. Shot near the St Louis Art Museum. Bullock was married to Engleman’s ex-wife Edna Ruth, who upon Bullock’s death collected $64,000.
1963: Engleman is suspected in the murder of Eric Frey, a business associate of Engleman at Pacific Drag Strip, in which Frey and the Engleman were partners. Struck him with a rock, pushed him down a well, and used dynamite to blow him up afterwards. He then divided the insurance proceeds with Frey's widow.
1976: Peter J. Halm. Shot in Pacific, Missouri. His wife, Carmen Miranda Halm, a former dental assistant trainee who had worked for Engleman and known him since childhood, ordered the hit to collect a $60,000 policy of life insurance on Halm.
1977: Arthur and Vernita Gusewelle at their farmhouse near Edwardsville, Illinois. Arthur was shot; Vernita bashed to death. Engleman then murdered their son Ronald in East St. Louis 17 months later so his widow Barbara could claim the millions in life insurance she had taken out on her husband, the sole heir to his parents' oil business. Engleman was not convicted of these three deaths, but confessed to them while in prison. Barbara Gusewelle Boyle subsequently sentenced to 50 years in prison for the murder of her husband. She was released from the Dwight Correctional Facility on October 10, 2009.
1980: Sophie Marie Barrera, owner of south St Louis dental laboratory. Killed in car bomb explosion. Engleman owed her over $14,000. Accused by her son, Frederick Barrera, of her murder.
Engleman was married twice, first to Edna Ruth and then to Ruth Jolley, with whom he had a son, David Engleman.
- Corbin Bernsen played the part of Engleman in Beyond Suspicion, a 1993 TV movie loosely based on the Susan Crane Bakos book Appointment for Murder.
- The story was told in the episode "Deadly Dentist" on the program The FBI Files.
- The 1996 movie The Dentist was based on this story.
- In the 2014 TV Show Fargo, hitman Lorne Malvo (Billy Bob Thornton) is shown acting as a dentist in order to track down a bounty.
- The story was told in the episode "Concealed Abscess" on the program Deadly Dentists, season 1 episode 3 which aired December 8, 2015. 
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- Cite error: The named reference
Concealed Abscesswas invoked but never defined (see the help page).
- ""Deadly Dentists" Concealed Abscess (TV Episode 2017)". imdb.com. Retrieved 20 December 2017.