LONDON, April 5 — The 15 British marines and sailors held captive in Iran for nearly two weeks arrived back home today. But Britain’s relief at their safe return was tarnished by questions about how they behaved during their detention and why they had been captured in the first place.

At the same time, Prime Minister Tony Bair abandoned the careful, diplomatic language he used during the crisis. Today, when the captives were safely en route to Britain, his tone became tough, almost antagonistic, as he spoke of possible links between the Iranian government and terrorism in Iraq.

Image Felix Carman greeting family members today at the Royal Marines Barracks in Chivenor, England. Credit... British Ministery of Defense

The British captives’ homecoming was carefully choreographed.

On Wednesday, before their release in Tehran, they were shown on television wearing outfits issued by the Iranian government — ill-fitting suits for the men and a headscarf and trousers for the lone woman, Leading Seaman Faye Turney. But when they arrived at Heathrow Airport outside London today, the eight sailors and seven marines were dressed once more in military clothing that had been flown in from Britain.