Joseph William Kappen (30 October 1941 – 17 June 1990), also known as the Saturday Night Strangler, was a Welsh serial killer who committed the rape and murder of three teenage girls in Llandarcy and Tonmawr, near his home town of Port Talbot, in 1973. Kappen is also suspected of committing a fourth murder in February 1976. Kappen is notable for being the first person ever to be posthumously identified as a serial killer via familial DNA profiling. He was also the first documented serial killer in Welsh history.