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Dr. Johannes OPDAM





Classification: Murderer
Characteristics: Poisoner
Number of victims: 2
Date of murders: 1952 / 1958
Date of birth: October 30, 1916
Victims profile: Arnolda van Eyl (his wife) / Arie Lodder (inmate)
Method of murder: Poisoning (prussic acid)
Location: Netherlands
Status: Sentenced to life in prison on June 8, 1954. Died in prison on October 14, 1983

Johannes Franciscus Alphonsus Marinus (John) Opdam was a Dutch murderer. Opdam was born in October 1916 in Surabaya, Dutch East Indies.

In 1936, he moved to the Netherlands. There he studied medicine and married Arnolda van Eyl, a teacher's daughter. During his wife's vacation in 1951, Opdam had an affair with the couple's maid, Nellie. Mrs. Opdam found out, but being a devoted Catholic, there was never any question of a divorce. Instead, Nellie was sacked. This did not stop Opdam from continuing his affair with the girl.

In 1952, Mrs. Opdam's health declined steadily until she died on the 24th of September. Doctor Opdam claimed it was a brain tumor, but the colleague who performed the post-mortem disagreed and gave the cause of death as 'unknown'.

Police were called to the case and a second examination of the body revealed Mrs. Opdam's body contained prussic acid. Johannes Opdam was arrested. During his trial, he at one point even accused his mother-in-law of committing the murder. On June 8th, 1954, Opdam was convicted to life in prison.

In the prison in Leeuwarden Opdam continued his dirty affairs. There he met Arie Lodder, who was also convicted for killing his wife. They agreed upon writing notes confessing each others murders, to be used when one of them would die.

In February 1958 Arie Lodder was found dead in his cell, which was next to the one of Doctor Opdam Lodder too had been poisoned with prussic acid and on his body was found the note, claiming that he had killed Mrs. Opdam.

It is still unclear how Opdam obtained the chemicals to poison Lodder. The note did not set him free, on the contrary, in 1961, Opdam was convicted again to life in prison, this time for the murder of Arie Lodder.

He remains the only one in Dutch juridical history to have been convicted twice to life in prison for two different murders.


  • J.H.H. Gaute and Robin Odell, The New Murderer's Who's Who, 1996, Harrap Books, London

  • Hans van Straaten, Moordenaarswerk, 1990, Amsterdam (Dutch)

  • Lennaert Nijgh, Moord & doodslag, 1990, Schoorl (Dutch)



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