The Brazilian boyfriend of a journalist who broke international news by exposing the NSA spying scandal was detained for hours in a London airport – and a British lawmaker wants to know why.

David Miranda was stopped at Heathrow Airport and questioned for nine hours. Miranda's partner is journalist Glenn Greenwald of the British newspaper The Guardian, who has written about NSA surveillance programs based on files he received Edward Snowden, the National Security Agency leaker who now has temporary asylum in Russia.

Keith Vaz, the chairman of the Home Affairs Select Committee, demanded to know why police stopped Miranda, who was held for nearly the maximum time authorities are allowed to detain individuals under the Terrorism Act's Schedule 7. The act authorizes security agencies to stop and question people at borders.

Miranda's cell phone, laptops and memory sticks were confiscated, Greenwald said.

"What needs to happen pretty rapidly is we need to establish the full facts," Vaz told the BBC. "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."

Miranda, 28, was stopped Sunday while traveling home to Brazil after visiting Germany, where he met with Laura Poitras, a U.S. filmmaker who has worked with Greenwald on the NSA story. The Guardian reported it paid for Miranda's flights, but did not immediately respond to a request for elaboration on what his role with the newspaper might be, if any.

Vaz said it was "extraordinary" that police knew that Miranda was Greenwald's partner, and the authorities were targeting partners of people involved in Snowden's disclosures.

"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," Vaz said.

Labour Party lawmaker Tom Watson questioned whether Home Office ministers had been told and described the detention as an "an embarrassment to the government."

"What I think we are going to see is this is sort of the intelligence services overstepping the mark— they are clearly trying to intimidate Glenn Greenwald — and that's an attack on journalism," Watson told the BBC.

London police acknowledged that they had detained a 28-year-old man at 8:05 a.m. He was released at 5 p.m. without being arrested, the Metropolitan Police Service said.

The Home Office defended Schedule 7 in a report last year, arguing it was designed to help authorities determine whether people crossing U.K. borders have been involved in the "commission, preparation or instigation of acts of terrorism." 

Border agents are not required to have reasonable suspicion before detaining a traveler.

Under Schedule 7, examining officers may require travelers to answer questions or provide documents. Detainees may be held for up to nine hours if they refuse to cooperate, the Home Office has said.

In most cases, those questioned under Schedule 7 are detained for less than an hour. Less than a tenth of 1 percent are held for more than six hours. Some 230,236 people were questioned under Schedule 7 from April 2009 through March 2012.

Based on reporting by The Associated Press.

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