Clark established incident rooms in Northumberland and Leith police stations , to liaise between the four police forces involved .
Hector Clark , the assistant chief constable of Northumbria Police , took overall charge of the investigation .
assistant chief constable established incident rooms in Northumberland and Leith police stations , to liaise between the four police forces involved .
Hector Clark , the assistant chief constable of Northumbria Police , took overall charge of the investigation .