Essex Police have advised people in Colchester not to visit isolated places alone, after two fatal knife attacks in the town in three months.
Nahid Almanea, 31, was found on Saturday near the University of Essex campus. She had been stabbed 16 times.
James Attfield, 33, was stabbed 100 times in Castle Park in March.
Police say a man in his fifties is helping them with their inquiries.
More top news
The 34-year-old from Coulsdon in Surrey died during the private party in Headley in the early hours of Monday, Surrey Police said.
The Home Office made the arrests at various restaurants across London on July 4.
Two years on from the Israel-Hamas conflict, Hamas cadets are being trained to carry out raids in a terrifying summer camp.