Tripoli, Libya (CNN)The call was simple, but it changed what an already dark business meant for one smuggler. Abu Walid knew his caller to be a devout man, a member of ISIS. And his request was chilling. Could he ship 25 of his people from Libya to Europe on a small boat for $40,000? Abu Walid -- not his real name -- declined. But it is a request that's becoming increasingly common, he told CNN, in the past two months. ISIS is trying to infiltrate this trade to get their people to Europe from the chaotic and near-failed state of Libya as the route from Turkey to Greece becomes more heavily policed. "Exploitation of migrant smuggling networks by ISIS in North Africa has only been a matter of...