Fadi Saqr is accused of mass killings of civilians in Tadamon, Damascus, where people say he must face justice

A Syrian rights commission is preparing a case accusing Fadi Saqr, a militia leader within the Assad regime, of involvement in crimes against humanity and war crimes, a senior Syrian official has told the Guardian.

Saqr is a former commander of the National Defence Forces (NDF) militia and is widely accused of involvement in the mass killing and forcible disappearance of civilians in the Tadamon neighbourhood of Damascus, as well as other parts of the Syrian capital.

Amjad Youssef is one of most-wanted fugitives in relation to slaughter of estimated 288 civilians under Assad

A Syrian former regime official suspected of leading a notorious civilian massacre revealed by the Guardian – and who became one of the country’s most-wanted fugitives after the fall of Bashar al-Assad – has been arrested by security forces, Syria’s interior ministry announced.

Amjad Youssef was captured in the Ghab plain area about 30 miles (50km) outside the city of Hama and had “been taken into custody following a carefully executed security operation”, the interior minister, Anas Khattab, said in a social media post on Friday.