Rebekah Brooks, her racehorse trainer husband and four others were picked up in an early morning sweep in and around London. They face charges of conspiracy to pervert the course of justice.
Brooks was a one-time protégé of Rupert Murdoch, who owned the now-defunct tabloid. It was shut down last summer amid allegations of illegal eavesdropping.
The move suggests that investigators may be focusing on a possible coverup of the scope of phone hacking rather than the illegal hacking itself.
The Associated Press contributed to this report.