CNN’s Isobel Yeung traveled to Libya to investigate refugees being tortured for ransom. Subscribe to watch the full report.

From the living room of her third-floor apartment in rural Germany, Abeba winces as she stares at her phone.

“This will be my final message,” her younger brother Daniel says in an audio message. “I understand that you may not have the financial means to assist me directly, and I never expected that from you. Please, just make sure my message reaches those who might be able to help.”

She and her husband don’t know exactly where her brother is. Somewhere in southern Libya. They’ve heard it’s an area called Kufra. What they do know is that every time he calls, or they receive a video, he’s being mercilessly tortured by men who remain off camera. Videos seen by CNN show Daniel being tied up, urinated on, kicked, and beaten with a metal pole. CNN is using pseudonyms for Daniel and Abeba because they fear retribution.

If his family doesn’t manage to gather the $10,000 being demanded by his captors, he may soon be dead.

CNN has spoken to dozens of individuals and families in their situation. Daniel is just one of an unknown number of migrants who are currently being tortured on a near daily basis, somewhere in Libya’s Sahara Desert.

Big business

Libya, in North Africa, has long been the transit country of choice for those hoping to travel across the Mediterranean Sea to reach Europe. At the northeast corner of the Sahara Desert, its vast wilderness marks the final leg on the African continent for those fleeing war, persecution, and lack of opportunity in search of a better life.

The passengers on this dangerous route change over time as conflicts ebb and flow. Recently, the vast majority have been coming from Sudan, embroiled in a brutal civil war which has displaced millions.

Inevitably, human smuggling is big business.

Much of it is relatively functional – insofar as clients pay several hundred dollars to be transported in bare