The Metropolitan Police has released this CCTV image of three people they want to speak to in connection with the death of Omer Jama Abdi a year ago. Detective Inspector Jamie Stevenson said he hoped people would recognise themselves in the CCTV pictures and make contact with the police.
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Kurt Cochran and his wife Melissa had been visiting London from the US to celebrate their 25th wedding anniversary and were due to fly home.
Rail union RMT have slammed the move saying the company MTR is set to make "a killing at the British taxpayers' expense".
The meeting was arranged in the wake of Wednesday's terrorist murder of four people in Westminster.