Via illegal cellphone call, North Korean brother reaches out to his South Korean sister

Two siblings reconnected when one took a huge risk to ask for financial help. It is estimated that about $10 million flows into South Korea each year as defectors reach out to try to assist their families.

In May this year, a North Korean defector in her 40s took a call from an unknown number at her office in the South Korean capital Seoul.

It was from her brother, who she had not seen for more than a decade, calling illegally from North Korea after tracking her down.

He was speaking from a remote mountainside near the border with China, and was in dire need of money to help treat another sister's late stage cancer, she said.

Accompanied by a Chinese broker, the brother had spent five hours climbing up the mountain, avoiding North Korean security and desperately searching for a signal on a Chinese mobile telephone. Contact with anyone in the South is punishable by death in North Korea, one of the world's most isolated states.

The broker was part of a growing group of people, mostly Chinese of Korean descent, who use ties on both sides of the border to funnel money to the North, an illegal and highly dangerous operation.