A 15-year-old from the city has been questioned following the incident in Wood Farm in October.
The teenager was arrested yesterday and bailed until 2 January 2020.
It’s after a man in his 40s was assaulted on Sunday 27th October, and sadly died on November 12th.
The attack was only reported to police after the victim attended hospital around a week after it happened.
Officers say they believe the man was assaulted in Wood Farm Woods or possibly outside the shops on Atkyns Road. They also believe a weapon was used.
Senior investigating officer, Detective Inspector James Senior of Force CID Oxford, said: “We continue to investigate this assault and at this time the death is being treated as unexplained.
“A home office post-mortem has been carried out and the cause of death has not yet been established.
“Further work is still being undertaken by the coroner and officers to establish the cause of the man’s death.”
Another boy, aged 16, from Oxford was arrested in November on suspicion of manslaughter and remains on police bail until the 16th of December.