Authorities are performing necropsies on the carcasses of 40 cats found in a storage-unit freezer in Queens — while hunting the Polish nurse suspected of leaving them there, sources said Tuesday.

Alicia Kosmaczewska, 66, lived in Brooklyn but may now be back in her native Poland, sources said.

She stopped paying for her storage unit in Long Island City in May, and after it was auctioned off, the new owner went in and found two chest freezers, officials said. He opened one to find the frozen cats.