- With the right immigration policy, refugees can play a valuable role in the war against terror, says Robert Verkaik
- German security services rely on intelligence passed on by members of its Muslim communities, he writes
Robert Verkaik is a freelance security correspondent specialising in Russian espionage and the war against terror. In 2016 he wrote "Jihadi John: The Making of a Terrorist", which traces Mohammed Emwazi's path from London schoolboy to ISIS executioner. Follow the author on Twitter. The views expressed in this commentary are his own.
(CNN)Donald Trump thinks that Angela Merkel's immigration policies have been a "catastrophic mistake" and has blamed the broader refugee crisis for Britain's decision to leave the EU.