A third man has been arrested on suspicion of the murder of an off-duty police officer who died after being assaulted in Greater Manchester.
PC Gareth Francis, 28, was attacked whilst walking home from a night out in Edgeley, Stockport, in the early hours of 20 January.
Paramedics treated him at the scene for a serious head injury and he was taken to Stepping Hill Hospital where he later died.
Two men, aged 20 and 21 and both from the Stockport area, were arrested on suspicion of Francis' murder and remain in police custody.
A third man, aged 20, has now handed himself into a police station on the night of 20 January and also remains in custody.
A motive for the attack is not known, but police confirmed they were not treating the assault as a robbery and do not believe a weapon was used.
Police are now appealing for witnesses to come forward.
The family of the murdered officer paid tribute to their "gorgeous son" who had brought "love and laughter" into their lives.
In a statement, the family added: "He was an amazing brother, boyfriend, grandson and nephew. We cannot imagine how we can face each day knowing that he is gone from our lives."
Stockport's divisional commander, Chief Supt Chris Sykes, said: "First and foremost, I would like to pass on my condolences to both Gareth's family and his colleagues in south Manchester. Gareth was a dedicated police officer with six years' experience and he will be greatly missed by his colleagues.
"However, the loss will be even greater for Gareth's family and I would like to reassure them that we have a team of detectives working round the clock now to establish exactly what happened this morning.
"We now have high visibility patrols in Edgeley town centre and I would urge anyone with concerns to approach officers there."
Ian Hanson, chairman of Greater Manchester Police Federation, said: "Gareth was a much-loved and well-respected member of the GMP family. We are all distraught at this news. Understandably, his team are devastated. Our immediate thoughts at this time are with his family, friends, colleagues and his partner."
Anyone with information is asked to call GMP's major incident team on 0161 856 9283, or Crimestoppers on 0800 555 111.