British police investigating phone hacking re-arrested former Rupert Murdoch aide Rebekah Brooks on Tuesday and detained her husband, a close friend of Prime Minister David Cameron, reports said. Brooks and her husband Charlie were reportedly among six people arrested at dawn on suspicion of perverting the course of justice by officers probing the scandal at Murdoch's now-closed tabloid, the News of the World. "The co-ordinated arrests were made between approximately 5am (0500 GMT) and 7am this morning," London's Metropolitan Police said in a statement. The 43-year-old Brooks resigned as chief executive of Murdoch's British newspaper unit, News International, in July, ending a stellar career which saw her edit both the News of the World and its daily sister paper The Sun. She quit just three days before being arrested for the first time on suspicion of the illegal hacking of mobile phone voicemails and bribing public officials. She has always denied any wrongdoing. News International confirmed to AFP that two current "non-editorial" staff had been arrested, identifying one of them as its head of security, Mark Hanna, but declining to name the other. The company and Brooks's spokesman David Wilson were both unable to confirm reports in the British media that Rebekah and Charlie Brooks were among those arrested. Scotland Yard said they had detained a 43-year-old woman and a 49-year-old man at their home addresses in Oxfordshire, west of London but refused to confirm their identities. It said the others arrested, also in the south of England, were aged between 38 and 48. "All six -- five men and one woman -- were arrested on suspicion of conspiracy to pervert the course of justice," it said. Brooks and her husband, a racehorse trainer, live in a wealthy area of rural Oxfordshire near Cameron, who has described Charlie Brooks as a "good friend" whom he has known since his schooldays at the elite Eton College. The arrests will likely be embarrassing for the prime minister, who flew to Washington on Tuesday for talks with President Barack Obama. Cameron's spokeswoman refused to comment, saying: "It's an operational matter for police." Murdoch shut down the News of the World in July after evidence emerged of widespread phone hacking at the tabloid, but his British newspapers continue to be dogged by allegations they covered up the practice. Last month, documents emerged suggesting that News of the World executives actively sought from the end of November 2009 to delete emails which could be used in legal action against the tabloid. A total of 22 people have now been arrested in the hacking probe. A further 23 have been held over the alleged bribery of public officials, including 11 current or former journalists at The Sun. Nobody has yet been charged in the two police investigations, although the News of the World's royal editor Clive Goodman and a private investigator were jailed in 2007 for phone hacking following a separate police probe. Cameron has tried to downplay his friendship with Rebekah and Charlie Brooks, but it came under the spotlight this month after it emerged the prime minister had ridden a horse that the couple had borrowed from Scotland Yard. The loan of the horse was seen as evidence of the cosy ties between police and Murdoch journalists. "I've known Charlie Brooks, the husband of Rebekah Brooks, for over 30 years. He's a good friend and he's a neighbour in the constituency -- we live a few miles apart," Cameron said on March 2 when asked about the horse. Cameron has also been drawn into the hacking scandal through Andy Coulson, another former News of the World editor who worked as his media chief until January 2011. Coulson was arrested on allegations of phone hacking and bribery last year. Rebekah Brooks has been dubbed Murdoch's surrogate daughter because of her closeness to the media mogul, for whom she has worked since she joined the News of the World when she was only 20 years old.