An 11-year-old boy was left with injuries to his face after being attacked by a dog in playing fields, police have said.
The boy was bitten and scratched on his cheek and needed hospital treatment.
Officers are appealing for information and witnesses after the incident in Stevenage on 27 July.
Police said the attack happened at playing fields off Chester Road and Canterbury Way at around 2.15pm.
The dog is described as brown and medium in size.
PC Georgina Yeabsley said: "This incident happened in the middle of the afternoon during the school summer holidays when there were several other people on the fields who may have seen what happened.
"If you witnessed the incident or have information that could help us to identify the dog's owner(s) please get in touch."
Anyone with information should call police on 101 with the reference 41/60436/22. Information can also be provided to Crimestoppers, anonymously, on 0800 555 111.