Investigations into animal welfare incidents are generally led by the RSPCA.
The charity has a long established expertise in both the investigation and prosecution of cases involving animal welfare and has built up a useful body of precedent and case law over the years.
However they can call in police and local council officials to help with their investigations.
County Council Trading Standards, for instance, may investigate instances involving farmed animals.
Cases put forward to the courts by the RSPCA are done so as private prosecutions - which mean they are not put forward by the CPS.