Johannes Franciscus Alphonsus Marinus O. was a Dutch murderer.

O. was born in October 1916 in Surabaya, Indonesia. In 1936, he moved to the Netherlands. There studied medicin and married Arnolda van Eyl, a teacher's daughter. During his wife's vacation in 1951, O. had an affair with the couple's maid, Nellie. Mrs. O. found out, but being a devoted Catholic, there was never any question of a divorce. Instead, Nellie was sacked. This did not stop O. from continuing his affair with the girl. In 1952, Mrs. O.'s health declined steadily until she died on the 24th of September. Doctor O. 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. O.'s body contained prussic acid. Johannes O. was arrested. During his trial, he at one point even accused his mother-in-law of committing the murder. On June 8th, 1954, O. was convicted to life in prison (which, in the Netherlands, means up to twenty years in prison). In the prison in Leeuwarden O. continued his dirty affairs. In February 1958 Arie Lodder was found dead in his cell, which was next to the one of Doctor O. Lodder had been poisoned with prussic acid and on his body was found a note, claiming that he had killed Mrs. O. In 1961, O. 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.

References

• 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)