Opposition activists have posted a video purporting to show at least 51 muddied male bodies alongside a river bank in the rebel-held Bustan al-Qasr neighbourhood of Aleppo.
The video, which is too graphic to post, follows a man walking along a river bank past dozens of male bodies with their hands tied and blood coming from their heads.
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Three people who had been arrested on suspicion of murder have been released without any further action.
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