Joël Bartels was a son of Emanuel Bartels and Roosje Komkommer. He was married on 5 November 1916 in Amsterdam to Saartje Cohen and together they had a daughter Betsy in 1917. Saartje Cohen passed away however on 5 February 1932 and Joel remarried on 11 June 1941 in Amsterdam to Saartje's sister Jetta Cohen, who was the widow of Levie Rimini since 1929.
City Archive of Amsterdam, archive card of Joel Bartels and family registration card of Levie Rimini.
In July 1941, an obituary was placed in Het Joodsche Weekblad for J. Bartels.
Het Joodsche Weekblad, 18 July 1941, 11