KNOWN WOLVES: A grim pattern in European attacks: Missed chances to pinpoint terrorism suspects beforehand. “In the London Bridge attacks, authorities had previously been told that two of the three assailants had shown extremist tendencies — echoing a pattern in other terrorist strikes. But tracking terrorism suspects and heading off attacks — even when someone has come under suspicion — has become increasingly difficult.” Bottom line is, mass immigration means there are more terror suspects than the security services can keep an eye on.