The murder of off-duty police officer Pc Ian Dibell sent shockwaves through a close knit community, residents have said.
Dr Natalie Mann, a criminologist at Anglia Ruskin University, who lives on the estate next to where the shooting occurred in Clacton, Essex, said the police helicopters were "above our houses all night."
She told The Huffington Post UK the shooting was frightening and shocking.
Pc Ian Dibell was gunned down on Monday
"It's very interesting and quite frightening as a resident of Clacton which is a very small town and a close knit community.
"But because it is a small town people tend to know someone who was involved, we hear rumours. It has sent shockwaves through the town.
"Because Pc Dibell was an innocent bystander, that's what makes this all the more shocking."
Dibell is thought to have been shot on Monday by Peter Reeve, 64, who was found dead in a graveyard in Writtle on Tuesday morning following an overnight man hunt.
Police said they had not fired at the suspect, who was found with head injuries in the Chelmsford area.
The family of Pc Dibell called him a "hero" and said he had paid for his actions "in the most devastating way".
Police seal off the graveyard in Writtle, where Reeve's body was found
"Policing was in his blood and Ian selflessly went to the aid of people in desperate need without fear or thought for his own safety. It was who he was, a hero," they said.
Police said a number of lines of inquiry were being pursued as to the motive.
He added: "There must have been some sort of catalyst that prompted the scale of a tragedy of this kind."
Constable Jim Barker-McCardle of Essex police described Pc Dibell as a "brave, respected and experienced neighbourhood officer" on Monday and said early indications were that he lost his life after deliberately intervening in an "extremely deadly situation".
David Cameron paid tribute to Ian Dibell in a press conference on Tuesday afternoon, saying his death was "a reminder of the immense debt" we owe the police. "[It's] a reminder of what the police do on our behalf every day of the year."