Senior MP to ask police why David Miranda, partner of reporter linked to whistleblower Edward Snowden, was detained at Heathrow Keith Vaz, chairman of the Home Affairs Select Committee, has said the nine-hour detention of David Miranda by officers during a stopover on his journey from Berlin to Rio de Janeiro, appears to be a new use of anti-terror laws. Miranda, partner of the US journalist Glenn Greenwald who interviewed the whistleblower, was stopped at 8.30am on Sunday morning while passing through Heathrow on a stopover on his way home from Berlin to the Brazilian city of Rio de Janeiro. Mr Vaz is to write to the Metropolitan Police to seek clarification on why the journalist's partner was held. The Labour MP acknowledged that the police security services should stop and speak to individuals if they have proper suspicions, and said this could be the case in the Miranda incident. The 28-year-old Brazilian citizen was held for nine hours under the Terrorism Act and his possessions, inlcluding his mobile phone, laptop, camera and memory sticks were confiscated, according to a column posted by Greenwald on the Guardian website. "This is a profound attack on press freedoms and the news gathering process," said Mr Greenwald. To detain my partner for a full nine hours while denying him a lawyer, and then seize large amounts of his possessions, is clearly intended to send a message of intimidation to those of us who have been reporting on the NSA and GCHQ. The Brazilian government complained about the detention of Miranda at Heathrow for nine hours, the maximum under the anti-terrorism law. "This measure has no justification since it involves an individual against whom there are no charges that can warrant the use of this legislation," the Brazilian foreign ministry said in a statement. Speaking on BBC Radio 4's Today programme, Mr Vaz said, "What needs to happen pretty rapidly is we need to establish the full facts. Now you have a complaint from Mr Greenwald and the Brazilian government - they indeed have said they are concerned at the use of terrorism legislation for something that does not appear to relate to terrorism - so it needs to be clarified, and clarified quickly. What is extraordinary is they knew he was the partner (of Mr Greenwald) and therefore it is clear people who are directly involved are being sought but also the partners of those involved. Bearing in mind it is a new use of terrorism legislation to detain someone in these circumstances... I'm certainly interested in knowing so I will write to the police to ask for the justification of the use of terrorism legislation - they may have a perfectly reasonable explanation. The Guardian reports that Miranda had spent the last week in the German capital meeting with US film-maker Laura Poitras, who has been working with Greenwald and the broadsheet on the Snowden files. Miranda was questioned under schedule 7 of the Terrorism Act 2000, which allows border officers to stop, search, question and detain individuals "to determine whether that person is or has been involved in the commission, preparation or instigation of acts of terrorism," the Guardian reports. A spokesman from the Home Office Office said today, "Schedule 7 forms an essential part of the UK's security arrangements-it is for the police to decide when it is necessary and proportionate to use these powers." According to official figures, more than 97 per cent of examinations under schedule 7 last less than an hour, and only one in 2,000 people detained is kept for more than six hours. "The actions of the UK pose a serious threat to journalists everywhere," Greenwald wrote. But the last thing it will do is intimidate or deter us in any way from doing our job as journalists. Quite the contrary: it will only embolden us more to continue to report aggressively. Greenwald, who is based in Rio de Janeiro, has interviewed Snowden and used 15,000 to 20,000 documents that Snowden passed to him to reveal details of the US National Security Agency's surveillance methods in a series of stories. The broadsheet also published stories about blanket electronic surveillance by Britain's GCHQ, also based on documents from Mr Snowden. A Guardian spokesman said, "We were dismayed that the partner of a Guardian journalist who has been writing about the security services was detained for nearly nine hours while passing through Heathrow airport. "We are urgently seeking clarification from the British authorities," he added. Widney Brown, Amnesty International's senior director of international law and policy, said, "It is utterly improbable that David Michael Miranda, a Brazilian national transiting through London, was detained at random, given the role his partner has played in revealing the truth about the unlawful nature of NSA surveillance. David's detention was unlawful and inexcusable. He was detained under a law that violates any principle of fairness and his detention shows how the law can be abused for petty vindictive reasons. A Metropolitan Police spokesman said, "At 08:05 on Sunday 18 August 2013 a 28-year-old man was detained at Heathrow Airport under Schedule 7 of the Terrorism Act 2000. He was not arrested. He was subsequently released at 17:00. Edward Snowden faces criminal charges in the United States after leaking documents disclosing previously secret US internet and telephone surveillance programmes. Russia rejected American pleas to send Snowden back to the United States for trial, granting him a year's asylum on 1 August. Additional reporting by Reuters and the Press Association