Thames Valley Police
A 49-year-old woman was pushed to the ground in Oxford's Christ Church Meadow and robbed.
Police said the mugging took place on Sunday, May 22, at about 7pm.
The woman had her purse taken.
A 15-year-old boy has been arrested on suspicion of robbery and released on bail until June 23.
Investigating officer PC Andy Hurst said: "We are conducting a thorough investigation and have made an early arrest, but I would encourage anyone who think they might know anything about this incident to call us."
Those with information should call 101.
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