Farmers in Wales who illegally cull badgers may be responsible for spreading Bovine TB.
That's according to a report published by the University of Bangor. It claims around one in ten of Wales' 14,000 livestock farmers had killed badgers in the twelve months leading up to the study.
The Welsh Government says badgers are protected animals, and the issue of illegally killing them is a matter for the police.
"You set a particular cull rate that you need to achieve for that to impact the disease and to decrease the rate of disease in an area" says Dr Paul Cross, from Bangor University.
"That's currently thought to be around 70% of all badgers. If you have an illegal killing rate going on the background that you're unaware of, you may have set the level of cull too high"