In December, rebel forces ousted Syrian president Bashar al-Assad, ending a 13-year civil war in the country that killed more than half a million people. Since then, Syrians have been trying to uncover the fates of the more than 100,000 people who vanished into the regime’s secret prisons, including thousands of children whose parents were thought to be disloyal to the regime. The Assad government and its proxies forcibly disappeared at least 3,700 children, according to the Syrian Network for Human Rights, and the true number could be far higher.

Hundreds of these children were separated from their families and secretly placed in orphanages, including six facilities run by an international NGO called SOS Children’s Villages. Many of them were given false identities to prevent their relatives from finding them, and some were then adopted away. The Times obtained copies of dozens of Assad-era classified documents and several vast databases created by Air Force Intelligence, an agency responsible for the operation, that together provide the clearest picture yet of its scale and cruelty. Below are the key findings of the investigation, which you can read in full here.

Syria’s secret police were in charge of placing children at orphanages.

The orders to remove children from their parents or other family members came from senior Air Force Intelligence officials. In numerous memos obtained by the Times, they tasked the Ministry of Social Affairs and Labor or the governor of Rural Damascus with finding orphanage placements, and instructed them to seek approval from the mukhabarat, or secret police, before making any further decisions about the children’s fate. The ministers and governors then ordered orphanages to keep the children hidden and block the release of any identifying information. The Times found that children were sent to at least nine facilities, six of which belonged to SOS Children’s Villages.

An international NGO played a crucial role.

SOS Children’s Villages International, headquartered in Austria, claims to be the world’s largest NGO for children without parental care. The organization operates in 127 countries and reports nearly $2 billion in annual revenue.

The Syrian case is not the first time that SOS has received children who were forcibly disappeared. In El Salvador, in the 1980s, the U.S.-backed military attacked villages suspected of supporting a leftist insurgency and kidnapped hundreds of children, who were then placed in orphanages, including those run by SOS.

SOS’s international spokesman, Bertil Videt, told The Times that the organization “did not intentionally contribute to the disappearance of any child, and we unequivocally disapprove of such practices.” But government records and interviews indicate that, in Syria, SOS staff received children directly from the regime’s secret prisons and, when families came looking for them, often refused to acknowledge that they had the children or release them to their relatives unless the mukhabarat signed off.