Vender Duncan
Executed American serial killer
About Vender Duncan
Lived 1928 – 1959 (aged 31).
Vender Lee Duncan (February 18, 1928 – May 29, 1959) was an American serial killer, rapist and burglar who sexually assaulted and killed three elderly women in San Francisco, California from 1955 to 1957. Following an arrest for burglary, he confessed to all his crimes, was convicted for two and eventually executed at the San Quentin State Prison in 1959.
Early life Vender Lee Duncan was born on February 18, 1928, in Sinclair City, Texas, a small unincorporated town in Smith County. A troubled youth who often got into fights, he lost an eye at age 17 and later served a sentence for assault with intent to commit murder after stabbing a man 24 times. At an indeterminate point in his life, he drifted towards San Francisco with his common-law wife, Helen Green, working as a house painter to make ends meet. When this proved insufficient, he started burglaring into houses, frequently preying on dwellings inhabited by the elderly and sometimes raping them. Duncan had a prior conviction for rape at the time of his murder trial.
Murders Marceline Herdlick On January 9, 1955, Duncan was walking through California Street when he spotted a second-floor apartment. After climbing up the fire escape, he peeked through the window, where he saw 82-year-old tailor Marceline Herdlick counting some money. Duncan then entered through the window, intending to attack her. Fearing that he might get caught, Duncan hit her in the face, causing the woman to fall to the ground. He then choked her to death before proceeding to copulate with her corpse. After assuring that Herdlick was dead, he then searched through the drawers in an attempt to find any money or valuables, before leaving. On his way, he accidentally dropped a small desk radio, which was left lying on the fire escape. As in his previous murder, he started viciously beating the frail woman, who quickly succumbed to her injuries. After rifling through the apartment in search of something to steal, Duncan then exited through the window, pulling the shades to obscure the body from view, partially tearing them off in the process.
The following day, Rev. William Hughes, a Roman Catholic pastor at the local Sacred Heart Catholic Church, became concerned for Manning, as she attended morning Mass regularly. He then contacted her neighbors, the Sansings, who also suspected that something had happened, noting that her mail box was full, something they considered unusual since Manning was expecting a letter from a niece from Quantico, Virginia, with whom she had plans to move in.
Ada Romig On April 5, 1957, Duncan was in the Grove Street area when he came across 68-year-old Ada Romig, an elderly pensioner who lived nearby. He attacked her in a vacant lot, repeatedly beating her and smashing a brick in her face, before dragging her to nearby Fulton Street. After hurling her body over a brick wall, Duncan continued dragging Romig until he found another vacant lot, where he left her. The semi-conscious woman was left lying in serious condition until a passer-by spotted her and alerted the authorities. She was only able to provide a partial description of her attacker, saying that he was "about 40" and had dark hair.
Arrest and confessions Just three days after the attack on Romig, Duncan struck again, going to the second floor of an apartment complex in Van Ness Avenue in the early morning and knocking on a random door. After he left the apartment, the still-dazed Provost staggered to the nearby police station to report the assault. Despite her injuries, which included a smashed left cheekbone; a fractured jaw and severe cuts and bruises, she was able to give an accurate description of her attacker - a black male, around 30, 5'6" and wearing hornrim glasses, coveralls and either a checkered/printed shirt. In his confession, he claimed that he was always drunk while committing the crimes, causing him to become very aggressive, and resorted to killing his victims because "he couldn't stand it when they started to scream." At the end of his confession, Duncan said that his conscience was now cleared and he intended to plead guilty to all of the crimes, as he preferred to be executed rather than spend the rest of his life behind bars.
Trial, imprisonment and execution Duncan's trial on April 15, 1958, with the prosecutors deciding to charge him solely for the 1955 murders. Contradicting his previous statements, he entered a double plea of not guilty and not guilty by reason of insanity. As per a new state law, there would be additional hearings to determine whether he was sane and thus eligible to receive the death penalty.
Over the ensuing months, he attempted to have his sentence commuted by appealing both to the Supreme Court of California and Governor Pat Brown, both of whom refused to do so. His death sentence was confirmed on May 25, 1959, when the SCOTUS refused to hear to his final appeal. As a result, Duncan was executed in the gas chamber at San Quentin State Prison on May 29, 1959.
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Important facts
People in Vender Duncan's life
Named in this biography and alive at the same time
Contemporaries
People whose lives overlapped Vender Duncan's
Frequently asked questions
Who was Vender Duncan?
executed American serial killer
When was Vender Duncan born?
Vender Duncan was born on 18 February 1928 in Sinclair City, Texas.
When did Vender Duncan die?
Vender Duncan died on 29 May 1959 in San Quentin State Prison, San Quentin, California.
Sources & further reading
Cite this page
APA: Biography.guide. (2026). Vender Duncan. https://biography.guide/vender-duncan/
MLA: "Vender Duncan." Biography.guide, https://biography.guide/vender-duncan/.
Chicago: "Vender Duncan." Biography.guide. https://biography.guide/vender-duncan/.
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