Police are appealing for anyone who might have seen Mr Nicol to contact them.
Supt. David Byrne speaks to ITV News about the investigation.
More top news
Chancellor George Osborne will seek to reassure financial markets on Monday morning following Britain's decision to leave the EU.
Eight crew members had to be rescued from a fishing boat after it started sinking a mile off the coast of Sunderland.
Drivers travelling north or southbound on the A1 near Newcastle and Gateshead are advised to expect delays until Wednesday morning.