ISIL killers freely roamed across Europe

FILE - In this file photo dated March 11, 2004, rescue workers cover up bodies alongside a bomb-damaged passenger train, following a number of explosions in Madrid, Spain. A gun assault on the Paris offices of satirical magazine Charlie Hebdo on Wednesday Jan. 7, 2014, was the deadliest terrorist attack in Frances recent history, and joins the roll of terror attacks in western Europe, including the bombs on rush-hour trains at Madrid's Atocha station that killed 191 people. (AP Photo/Paul White, FILE)

‘Man in the hat’ left a trail across EU that led to UK and arrests in Birmingham are thought to have been triggered by capture of the Belgian jihadist.