Tom Ridge: 'Multiple sources' on airport threat
Former US Secretary of Homeland Security Tom Ridge has told the BBC that there must have been credible evidence from more than one source for the US to increase security checks on flights coming into the country.
Mr Ridge said that he would think that several sources - including one which has provided accurate information in the past - must have provided the information leading to this decision.
He explained how he thought the decision to increase security levels would have been made.
03 Jul 2014