- Knowles, who walks with a limp, is 5ft 8in, heavily built and has tattoos on both arms and a scar across his left eye
- He was wearing a light grey tracksuit and a black cap when he was last seen
- People are advised not to approach Knowles but to call 999 if they see him
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The 24-year-old was unarmed and the incident is not being treated as terror-related.
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