A woman was bitten by a dog while walking in Salcey Forest, near Northampton.
The woman was walking her own dog when a Staffordshire Bull Terrier with no obvious owner appeared. She put her dog back on the lead but the bull terrier started to fight it, during which the woman was bitten on the leg.
The incident happened sometime between 9.30am and 10.15am last Saturday (May 4), near to where scouts and cubs have recently been building dens.
A spokesman for Northamptonshire Police said there was a man a short distance away who it is believed may have been the owner of the bull terrier.
There were a number of other dog walkers about at the time and officers are appealing for anyone who witnessed the incident, or has any information about the bull terrier or its owner, to contact Northamptonshire Police on 101.
Alternatively, they can call the independent charity Crimestoppers anonymously on 0800 555 111 or use the anonymous online form at www.crimestoppers-uk.org.