LONDON: Fourteen crew members of a Pakistan International Airlines (PIA) flight were detained at London's Heathrow Airport and later let off after the aircraft was thoroughly searched for over two hours post-landing.The Dawn and the Express Tribune newspapers quoted PIA spokesperson Mashhood Tajwar, as saying that Flight PK-785 from Islamabad to London arrived at Heathrow Airport at 2.50 p.m. on Monday, and after passengers disembarked, the flight crew and aircraft were searched by authorities.It is yet not known why the crew was detained. Tajwar said nothing was found on the plane, adding that the PIA plans to take up the case with the British aviation authorities.Other reports in Pakistani media said the crew was detained over 'alleged security threats via confidential information' and their passports withheld.