The hunt for a gunman suspected of killing an off-duty policeman in Essex has continued through the night.PC Ian Dibell, 41, was shot dead in Clacton-on-Sea on Monday afternoon - his chief constable said he had been a "brave neighbourhood officer".
Essex Police have vowed to "not rest" until the man suspected of the attack, Peter Reeve, 64, has been detained.
PC Dibell is thought to have been killed when he tried to intervene in a dispute. A second man was wounded.
Mr Reeve, who is believed to be armed, has been described as dangerous by police, who said he should not be approached.
He is described as white, about 5ft 10ins tall with short, greyish hair, wearing jeans and possibly glasses. He comes from the Clacton area.
Speaking at a news conference on Monday night, Essex Police Chief Constable Jim Barker-McCardle said PC Dibell was "an experienced and professional neighbourhood police officer" who "deliberately intervened in what he knew was an extremely deadly situation".
The chief constable said: "Policing is a family and we are all hurting.
"This dreadful event reminds us all that policing is a mission that ultimately some die for.
"We will not rest until we have Peter Reeve in custody - the investigation will continue round the clock."
Residents of Redbridge Road in the seaside town described hearing shooting and screaming at about 15:40 BST.
A 45-year-old woman, who lives yards from the scene, said she heard "a lot of commotion" and saw a man running up the road.
Hazel Field, 75, who lives in Redbridge Road, said: "I was in the garden at the time and heard a gunshot, followed by a woman's scream.
"Then I heard another gunshot, followed by about five more."
Eric Long, 80, said he saw the gunman from his window: "I saw him standing with some kind of revolver.
"He was chasing somebody, firing as he went."
When police arrived at the scene, they found PC Dibell dead and another man with serious leg injuries lying in the street. He is receiving hospital treatment for gunshot wounds to the leg.
A white tent now stands where the police officer was shot.
Paying tribute to him, Mark Smith, chairman of the Essex Police Federation, said: "Constable Ian Dibell was a dedicated professional officer who, even though off duty, has paid the ultimate sacrifice for his bravery and selfless actions in trying to protect his local community."
Sir Hugh Orde, president of the Association of Chief Police Officers, said: "The death of our colleague in Essex is deeply sad news for the police service.
"PC Ian Dibell died while knowingly walking towards danger, as police officers are called upon to do on behalf of the public they serve.
"The courage he showed in stepping up to do his duty, without thought for his own safety, sums up what it means to be a police officer."