There was a huge police presence in the area Senior Investigating Officer, Detective Chief Inspector Andy Shearwood, of the Major Crime Unit, said: “We are continuing to investigate the tragic death of Mr Porter, which took place on 26 April on the Aylesbury Arm of the Grand Union Canal. “Our team continue to work to establish the full circumstances of the incident, and I am now appealing to a specific potential witness to please come forward with any information they may have. Police were seen taping off parts of the path near the canal “The image we are releasing was taken at 12.10pm on April 26, shortly before the incident took place, and shows someone who appears to be walking a dog along the towpath, near to Broughton Crossing, located very near to the car park on Broughton Lane.