It’s odd that in the UK a person who buys stolen property legally owns it.
They do not legally own it in the sense that the original owner will not be able to eventually recover it after the fraud is unravelled.
Your instinct that this is odd is correct. It is odd because it isn't actually true. The statement of a police officer made while standing on the street outside someone's house deciding whose story to believe is not the final legal verdict on this case.