Semyon Stefanovich Serafimovich (19 December 19107 August 1997) was the first person to be prosecuted under the War Crimes Act 1991 in the United Kingdom. During World War II he was a commander in the Belarusian Auxiliary Police under Nazi occupation.Safe Haven: The United Kingdom’s Investigations into Nazi Collaborators and the Failure of Justice. Jon Silverman and Robert Sherwood, Oxford University Press, 2023.

Serafimowich, a Belarusian who was a carpenter by trade, was granted refugee status when the War ended and migrated to the UK with his wife, who died in 1993. British authorities initially investigated Serafimowich in 1947 and found that he had entered the United Kingdom illegally by falsely stating that he had been a member of the Polish army during the war, but no action was taken against him.

In 1995 Serafimowich was arrested and charged with four counts of murder in respect of Jews in Belarus in 1941/2.Report of the Secretary-General, United Nations General Assembly. The scope and application of the principle of universal jurisdiction A/66/93 20 June 2011. https://documents.un.org/doc/undoc/gen/n11/380/74/pdf/n1138074.pdf?OpenElement Two of the charges related to alleged murders that occurred in the town of Turets on 27 October and 4 November 1941. The other charges related to the alleged killing of a Jew on 9 November 1941 in the town of Mir (where about 3,000 Jews were held in the Mir Ghetto), and another alleged murder some time between December 1941 and March 1942 in the village of Kryniczne,Britain charges man with war crimes. UPI 13 July 1995. https://www.upi.com/Archives/1995/07/13/Britain-charges-man-with-war-crimes/2910805608000/ 15 kilometres north of Mir. During the committal hearing that followed, sixteen witnesses testified that Serafimowich played a role in the extermination of more than 3,000 Jews in and around Minsk, the capital of Belarus.Mirror.co.uk 23 October 2007. https://www.mirror.co.uk/news/uk-news/i-was-devastated-my-grandad-was-branded-a-nazi-515481. According to historian Eugeniusz Mironowicz, Serafimowich and his associates murdered families that they had lived and worked with for years. Mironowicz, Eugeniusz. Ukraińcy, Rosjanie and Żydzi na Białorusi i w okresie okupacji iemieckiej Беларускі гістарычны зборнік 42. Беларускае гістарычнае таварыства 42, Białystok, Poland 2014.

The case against Serafimowich was withdrawn when a jury at the Old Bailey formed the view that he was unfit to be tried because of reduced competence resulting from dementia.War Crimes Case Abandoned: FINAL Edition. (1997). The Washington Post. The outcome subsequently raised questions around the efficacy of criteria used to determine a person's mental competence, as well as the validity of the legislation used to prosecute Serafinowicz.McMurtrie, Sheena. A Challenge to the Validity of the Parliament Act 1949: An Opportunity Lost. Statute Law Review, Volume 18, Number 1, pp. 46-57, 1997

Serafimowich died soon after the trial ended, on 7 July 1997 at the age of 86,England & Wales, Civil Registration Death Index, 1916-2007 and is buried at All Saints Church, Banstead, Surrey, England.

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