As a cat and lurcher owner I can see both sides, I don't think the police will be interested, as others have said they don't bother about real crime. The rabbit's owners should have made sure their pets were secure, but a peace offering wouldn't go amiss then you can say you've done all you can to put the missus' mind at rest. If one of my lurchers or someone elses killed one of my cats I would accept it as nature (and as long as it was a clean kill at least they wouldn't have suffered, unlike in a road accident), however if someone else's dog came into my garden and did it I would feel that