Many emerged frail and emaciated into the bright December sunlight, greeted by weeping family members who had no idea they were still alive.
Verified videos from Damascus showed dozens of women and small children being held in cells, the rebels opening the doors telling them not to be afraid.
There are conflicting reports of underground cell blocks yet to be reached.
One shaven-headed, shaking man in Sednaya had been so ill-treated he had lost his memory and struggled to talk.
Many Syrians were over the years brusquely informed by authorities that their relatives had been executed, sometimes years earlier.
For many, there is still an agonising wait, hoping against the odds that loved ones will be found alive.
“Some of them have a small hope, a window of hope, that their children will be alive. »