Four more out of the 200 Chibok schoolgirls kidnapped by Boko Haram, raising hopes for the young prisoners still held captive, according to a report.

The free girls, all between ages 16 and 18, escaped with the help of a teenage boy prisoner, who managed to get them out of the camp, according to Stephen Davis, a British-Australian negotiator who had tried to bargain with the extremist Islamic group for the schoolgirls’ freedom.

The girls, guided by the setting sun, walked west for three weeks, finally arriving in a Nigerian village, starving and traumatized.

“They were amazing — to first escape and then walk for weeks,” Davis said.  “They are the only ones that have escaped from a Boko Haram camp.”

Davis said the girls had been told that if they fled Boko Haram, their families would be killed.