Ms Patel reiterated a tough stance on immigration, pledging to "end the free movement of people once and for all".
The alleged incident occurred on the margins of the clash between Portsmouth and Southampton.
Boris Johnson spoke in front of a group of police officers in Wakefield on Thursday.
A poll of thousands of officers showed 81% want the devices to make them feel safer while on duty.
The University of Derby have said the post has since been removed from Facebook.
Specialist search and rescue teams were joined by large numbers of volunteers scouring the river banks.
Grieving officers have laid floral tributes at the scene in Berkshire where their colleague was killed.
Pc Andrew Harper, 28, died following a ‘serious incident’ on Thursday.
Figures show a higher number of officers are being attacked in recent years.
Forensics officers have been seen searching a caravan site some three miles away from the scene of the death.