Barcelona Attack: Younes Abouyaaqoub Evaded Capture for Days, But Can Security Services Be Blamed?

“It is kind of searching for a needle in a haystack,” says Raffaello Pantucci, director of international studies at the London-based defense think tank Royal United Services Institute (RUSI). “If you have got someone who doesn’t come from a network, then you don’t know where to start looking. You’ve just got to start digging through what you know.”