A man has been arrested on suspicion of murder after an off-duty police constable was beaten to death in Liverpool.
Neil Doyle was attacked by a group of men during a Christmas night out with colleagues from Merseyside Police.
The 36-year-old got married in July and was due to go on honeymoon next month.
Two other off-duty officers suffered facial injuries in the attack, which took place near the Aloha nightclub in Colquitt Street at around 3.15am on Friday.
Officers are investigating the possibility they were targeted because of their jobs.
The 28-year-old suspect walked into a police station on Friday evening and is being interviewed by detectives.
Mr Doyle, who joined the force in May 2004, was taken to the Royal Liverpool Hospital, but died a short time later.
A post-mortem examination concluded he died from fatal bleeding around the brain, consistent with an assault.
Chief Constable Sir Jon Murphy described the investigation as being at a "very early stage".
He said: "On behalf of everybody connected with Merseyside Police I extend our heartfelt and sincere condolences to his wife Sarah and the rest of his family.
"Constable Doyle was enjoying a Christmas night out with his work colleagues.
"At around 3.15am Neil left the Peacock bar and walked with two colleagues along Colquitt Street in the city centre.
"The three officers were subjected to an apparently unprovoked and vicious attack by a group of males."
Mr Doyle had received a commendation for his actions in arresting three men after a violent robbery.
Peter Singleton, chairman of Merseyside Police Federation, said the police community was "devastated" by his killing.
"He exemplified the British bobby. He was a solid, good, hard-working, honest copper," he said.
The two other officers required hospital treatment. One suffered a fractured cheekbone.