Sarah Abdallah is one of the most influential Twitter users commenting on conversations about the conflict in Syria,

As the investigation continues into another alleged chemical attack in Syria, one group of influential online activists is busy spreading their version of events.

Inspectors from the Organisation for the Prohibition of Chemical Weapons (OPCW) are attempting to access the previously rebel-held town of Douma, where medical organisations and rescue workers say President Bashar al-Assad’s forces dropped bombs filled with toxic chemicals in an attack on 7 April, killing more than 40 people.

The Syrian government and its key ally, Russia, say the incident was staged. But the US, UK and France – who support the opposition to Mr Assad – say they are confident that chlorine and possibly a nerve agent were used.

Despite the uncertainty about what happened in Douma, a cluster of influential social media activists is certain that it knows what occurred on 7 April.

They’ve seized on a theory being floated by Russian officials and state-owned media outlets that the attacks were “staged” or were a “false flag” operation, carried out by jihadist groups or spies in order to put the blame on the Assad government and provide a justification for Western intervention.

The group includes activists and people who call themselves “independent journalists”, and several have Twitter followings reaching into the tens or hundreds of thousands.