The investigation is part of a wider police probe into alleged illegal reporting tactics at News Corp.

WSJ: Ex-Sun Reporter Pleads Not Guilty

The scandal erupted after HP director Tom Perkins complained about the tactics used in the probe, eventually leading to the departure of Dunn, who authorized the probe, from HP's board of directors.

FORBES: Ex-HP Chair Avoids Jail

The probe is part of a wider criminal investigation into illegal reporting tactics, including email and voice-mail interception.

WSJ: Two U.K. Journalists Arrested in Bribery Probe