Mr. Greenwald’s partner, David Michael Miranda, 28, is a citizen of Brazil. He had spent the previous week in Berlin visiting Laura Poitras, a documentary filmmaker who has also been helping to disseminate Mr. Snowden’s leaks, to assist Mr. Greenwald. The Guardian had paid for the trip, Mr. Greenwald said, and Mr. Miranda was on his way home to Rio de Janeiro.

Mr. Miranda, Mr. Greenwald said, was told that he was being detained under Section 7 of the British Terrorism Act, which allows the authorities to detain someone for up to nine hours for questioning and to conduct a search of personal items, often without a lawyer, to determine possible ties to terrorism. More than 97 percent of people stopped under the provision are questioned for under an hour, according to the British government.

“What’s amazing is this law, called the Terrorism Act, gives them a right to detain and question you about your activities with a terrorist organization or your possible involvement in or knowledge of a terrorism plot,” Mr. Greenwald said. “The only thing they were interested in was N.S.A. documents and what I was doing with Laura Poitras. It’s a total abuse of the law.” He added: “This is obviously a serious, radical escalation of what they are doing. He is my partner. He is not even a journalist.”

London’s Metropolitan Police Service, which had jurisdiction over the case, said in a statement that Mr. Miranda had been lawfully detained under the Terrorism Act and later released, without going into detail. “Holding and properly using intelligence gained from such stops is a key part of fighting crime, pursuing offenders and protecting the public,” the statement said.

The Guardian published a report on Mr. Miranda’s detainment on Sunday afternoon.

Mr. Greenwald said someone who identified himself as a security official from Heathrow Airport called him early on Sunday and informed him that Mr. Miranda had been detained, at that point for three hours. The British authorities, he said, told Mr. Miranda that they would obtain permission from a judge to arrest him for 48 hours, but he was released at the end of the nine hours, around 1 p.m. Eastern time.

Mr. Miranda was in Berlin to deliver documents related to Mr. Greenwald’s investigation into government surveillance to Ms. Poitras, Mr. Greenwald said. Ms. Poitras, in turn, gave Mr. Miranda different documents to pass to Mr. Greenwald. Those documents, which were stored on encrypted thumb drives, were confiscated by airport security, Mr. Greenwald said. All of the documents came from the trove of materials provided to the two journalists by Mr. Snowden. The British authorities seized all of his electronic media — including video games, DVDs and data storage devices — and did not return them, Mr. Greenwald said.

A spokesman for the British Foreign Ministry said the episode was a “police matter” and would provide no further comment. Civil rights groups in Britain have criticized Section 7 of the Terrorism Act, accusing the authorities of using the provision to arbitrarily stop and detain travelers, particularly Muslims. The British Home Office has said it is reviewing the provision in an effort to address the concerns.

A lawyer for The Guardian in London was working on trying to understand what had happened, as were foreign-affairs officials for Brazil both in that country and in London, Mr. Greenwald said. He said that he received a call from the Brazilian foreign minister about 40 minutes after alerting the Brazilian government, and that the Brazilian authorities were outraged.

Sergio Danese, the under secretary for consular affairs at Brazil’s Foreign Ministry, said Brazil’s consul general and embassy officials in London had worked to resolve the situation. In a statement, the Brazilian Foreign Ministry expressed “grave concern” about the incident, which it said was “without justification” since there could be no “legitimate” accusations that Mr. Miranda fell under the Terrorism Act.

Charlie Savage reported from Washington, and Michael Schwirtz from New York.

Article source: http://www.nytimes.com/2013/08/19/world/europe/britain-detains-partner-of-reporter-tied-to-leaks.html?partner=rss&emc=rss