An 84-year-old Nazi war criminal serving two life sentences for the murder of 18 Jews has died in a British jail, authorities said Monday. Anthony Sawoniuk, the only person to be convicted of Nazi war crimes in a British court, died in Norwich Prison, in eastern England, on Sunday, a spokeswoman for the government's Home Office said. The death was attributed to natural causes. Sawoniuk had been suffering from a terminal illness and police said his death was not being treated as suspicious. Sawoniuk, originally from Domachevo, Belarus, moved to south London in 1946 where he worked as a railway ticket collector. During a war crimes trial in Britain in 1999 Sawoniuk pleaded innocent to involvement in Nazi genocide in Eastern Europe 50 years earlier, but witnesses implicated him in a series of murders in his hometown.