However without definitive proof, questions remain and Dr Haji acknowledges there is a lack of proper research into CS gas use and SCD deaths.

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They were thrown into the back of an armoured personnel carrier and that a soldier fired a canister of CS gas inside, he said.

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Following his arrest on 25 July, 2011 in Windermere, Cumbria, officers also recovered a can of CS gas from an address in Preston linked to Slee.

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