Michael Fearon, 57, of Timbercliffe, Littleborough, had pleaded guilty to murder at a previous hearing at Manchester Crown Court.
BBC: Vincent Kershaw death: Michael Fearon jailed for murder
2.
The court was told that Fletcher first had sex with her while on duty on 21 July 2010, when he attended her house in Littleborough to make sure she was safe.
BBC: Sex-on-duty Greater Manchester police officer jailed