Lawyers Challenge Detention of Greenwald's Partner in London LONDON - In London's High Court on Wednesday, lawyers challenged the legality of the temporary detention of David Michael Miranda, the partner of Glenn Greenwald, a journalist who has been writing about the secret documents taken by a former analyst for the National Security Agency, Edward J. Snowden. Mr. Miranda, 28, was held at Heathrow Airport for nine hours in August while on his way from Berlin to Brazil, and his computer, telephone and memory sticks were confiscated. They contained around 58,000 encrypted, secret files from the Snowden archive, the British government said. British intelligence officials are still trying to decrypt all of the files to see exactly what Mr. Miranda was carrying, but they have argued that the stolen documents and the stories written based on them have damaged national security and aided global terrorism. Mr. Miranda had been traveling home to Brazil, where he lives with Mr. Greenwald, after visiting Germany, where he met with Laura Poitras, an American filmmaker who has worked with Mr. Snowden and Mr. Greenwald on the N.S.A. articles. Mr. Miranda has said he did not know the contents of the files he was carrying. After his return to Brazil, he filed suit, asking for a judicial review of his detention and the return of his property. At a preliminary hearing in court, his lawyers challenged the legality of using counterterrorism powers at ports of entry in this case, arguing that the law was misused and that Mr. Miranda's fundamental rights were violated. Matthew Ryder, Mr. Miranda's lawyer, argued that the case hinged on Schedule 7 of the Terrorism Act 2000, which gives officers the power to stop, question and detain people at ports even if wrongdoing is not suspected. "If the court finds that such a power was used proportionally in seizing journalistic material in this way, we ask the court then to consider if Schedule 7 is compatible with fundamental rights - in particular, the right to freedom of expression," Mr. Ryder stated in court, according to news agencies. This case illustrates vividly why it is not compatible. But a lawyer for Britain's Home Office, Steven Kovats, said Mr. Miranda's detention was justified because publication of the Snowden material could aid terrorism and put lives at risk. Oliver Robbins, a deputy national security adviser, said in evidence submitted Wednesday that British security services had a duty to determine whether the materials Mr. Miranda were carrying were a threat, Reuters reported. The hearing is expected to last two days.