British police investigating tabloid phone hacking on Friday arrested a 47-year-old woman on suspicion of trying to pervert the course of justice.
The woman, whose name was not disclosed by police, was detained at her home and taken to a police station in Essex, east of London.
The BBC and other media identified her as Cheryl Carter, long-serving former assistant to ex-News of the World editor Rebekah Brooks and other executives at Rupert Murdoch's News International.
News International declined to comment.
Detectives have arrested 23 people as part of investigations into phone hacking, computer hacking and police bribery at the Murdoch-owned News of the World. No one has been charged.
Murdoch shut down the paper in July after evidence emerged that its employees had routinely eavesdropped on the cellphone voice mail messages of celebrities, sports figures, politicians and even crime victims.
The scandal has spawned a huge police investigation and a public inquiry into media ethics.