Ask for the name of the Japanese cartoon, both sisters are policemen,

I haven't found this one you mentioned either.

But I have seen a film of three sisters, the youngest one has short hair, the other two have long hair, and the three are always stealing art (all related to their dead father). Second sister's boyfriend is a policeman and always catches thieves who steal art, but he never knew that the person he wanted to catch was his girlfriend, because he never caught him once.

Three sisters called Cat's Eye.

It's also very relaxed and funny. You're not talking about this, are you?