Police arrested Cheryl Carter, who was personal assistant to Rebekah Brooks, the deputy editor of The Sun and editor of News of the World, on suspicion of attempting to pervert the course of justice, The Daily Telegraph reported.
Scotland Yard officers arrested Carter at her home in Essex Friday.
"The woman was arrested at approximately 6:55 a.m. She is currently in custody at an Essex police station," a spokesman for Scotland Yard said.
Brooks was arrested in July for phone hacking and bribing police officers.
Scotland Yard said about 800 people's mobile phones were hacked by News of the World, which was shut down.