Temporary Detective Chief Superintendent Gordon Lang said he did not "anticipate any more arrests" in the double murder case.
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Turning wet and breezy from the west overnight.
The unknown man was found on the street outside University College Hospital in London after suffering a heart attack on Boxing Day.
'Amateurish and incompetent' thieves Jason Baccus and Kevin Downton shot businessman Guy Hedger during a bungled robbery.