Senior police officer under investigation over hacking of Milly Dowler's phone Craig Denholm, pictured in 2002, when he a detective chief superintendent at Surrey police. Photograph: Chris Young/PA The second most senior officer at Surrey police is being investigated by the Independent Police Complaints Commission over claims he failed to act when he discovered the News of the World had hacked Milly Dowler's phone. Deputy Chief Constable Craig Denholm, who was in overall charge of Operation Ruby - the investigation into the girl's disappearance in March 2002 - is to be the subject of an independent investigation by the police watchdog. The inquiry centres on allegations that Denholm knew Milly's phone had been hacked by the News of the World in 2002 and did not act. Surrey police and the police authority referred his conduct to the IPCC on 21 June and the police watchdog announced on Thursday it would be carrying out an independent investigation. Denholm was working as a commander in the counter-terrorism unit at Scotland Yard under Assistant Commissioner John Yates in 2009, shortly before Yates announced that the phone-hacking inquiry would not be reopened following revelations in the Guardian. As the detective who had overall control of the Dowler investigation from 2002 onwards, it has been alleged that Denholm was aware that the tabloid newspaper had illegally accessed information from the missing girl's phone following a meeting with two reporters from the Sunday newspaper in 2002. In its statement, the IPCC said it was "considering whether Mr Denholm was aware during Operation Ruby that the NOTW had accessed Milly Dowler's voicemail in 2002 and his handling of that information." The IPCC said on Thursday it was also beginning an independent investigation into the senior investigating officer on Operation Ruby from 2006 onwards, Detective Chief Inspector Maria Woodall - now a detective superintendent. The inquiry will examine whether she knew about the phone being hacked. The IPCC said it would focus on what information she provided to the Surrey police internal investigation into the force's response to allegations that Milly's phone had been hacked. In a statement jointly released by Surrey police and the IPCC, the Dowler family saidthey welcomed "the proper investigation of what happened at Surrey police 10 years ago. They regret that the passage of time means that some individuals can now no longer be investigated. The family have no further comment to make at this time. Surrey police said both Denholm and Woodall remained serving officers and had not been suspended, or placed on restricted duties. At Surrey, Denholm is known to be one of the main advocates of bringing more privatisation into policing and is responsible for the "risk and reputation" of the force. He is also the "champion for diversity and leadership" within the force. Denholm was appointed deputy chief constable of Surrey - where he had previously worked for seven years - in June 2009. Before moving to Surrey for his second tenure to take up the deputy chief constable role, he spent a year at the Metropolitan police as a commander in S015, counter-terrorism, where Yates was in charge. He left in June - a month before Yates carried out a review into the original phone-hacking inquiry as a result of revelations in the Guardian that there could have been thousands of victims. Yates ruled out reopening the investigation after his review, which lasted less than 24 hours. Denholm - whose career started at the Met - has also worked for the National Criminal Intelligence Service (NCIS) and Hampshire constabulary.