Syrian government forces carried out at least eight chemical attacks during the final month of the battle for Aleppo, killing at least nine and injuring approximately 200 civilians, Human Rights Watch (HRW) charged last week. The advocacy group said it interviewed witnesses, collected photos, and reviewed video footage indicating that chlorine bombs were dropped from government helicopters from Nov. 17 to Dec. 13, 2016. “The pattern of the chlorine attacks shows that they were coordinated with the overall military strategy for retaking Aleppo, not the work of a few rogue elements,” says Ole Solvang, deputy emergencies director at HRW. If confirmed, the attacks would be a violation of the 1993 Chemical Weapons Convention, an international treaty Syria signed in 2013 that bans the use of chemical weapons. Syrian forces launched an offensive in November to seize eastern Aleppo, a key battleground in Syria’s nearly six-year civil war. The regime announced on Dec. 22 that it had taken full control of the city. President Bashar al-Assad’s regime has repeatedly denied using chemical weapons.