Mr Barker-McCardle said officers were following a number of lines of inquiry as to the motive for the attack. Neighbours suggested there may have been a dispute over car-parking which spiralled out of control.
Mr Barker-McCardle said Pc Dibell, who lived near the crime scene in Redbridge Road, had "paid the ultimate price" after stepping in to protect a member of the public while off duty.
Reeve is understood to have had several family members living near the churchyard and some residents said he may have had a relative buried there. A cordon remained in place around All Saints Church and a white forensic tent was erected towards the western edge of the churchyard amongst several graves.
Mr Dibell's family, several of whom are police officers, issued a statement saying they were devastated by his death. They added: "We are immensely proud of Ian and the courage he showed. We take some comfort from his bravery. 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."
Mr Marshall's ex-wife, Pauline, told reporters she did not know of Reeve but added her voice to tributes to Pc Dibell. She said: "We are so grateful to the police officer. He is clearly a hero who saved Trevor's life."