'We believe he's unarmed, although it's possible that he has got hold of a knife or even fashioned a club or stick. In that sense, our advice to members of the pubic is to treat him as a dangerous person,' he added.
'If you see him, don't confront him. Stay calm, and walk away and call the police immediately.'
'Take note of where he is,what he's wearing. Any description of him, direction he's going and call the police.'
'That's the best the public can do. Please do not try to confront him. That will not be the most prudent way.'