Claims that 10,000 greyhounds have been killed in the past 15 years because they couldn't race fast enough should be investigated, an MP has said.
Newspaper reports say one man in County Durham is behind the killings and that there is film evidence of the creatures being put down with a bolt gun.
Bolt guns are used to kill farm animals. It is not illegal, but there are big concerns about the greyhounds.
MP Eric Martlew has called for an urgent investigation into the claims.
Now the organisation that looks after the sport of greyhound racing says it will investigate and take action against anyone responsible.
Greyhounds are racing dogs and when they don't do well in competitions, it's feared that many are abandoned.
It was reported that some owners had been paying for their animals to be killed by bolt gun.
Mr Martlew said: "For a long time now people have thought this kind of thing has been going on but without any evidence.
"I think the industry is in denial about it."
A government spokesman said: "We would welcome the chance to look at the evidence gathered in this case."