Crack Auckland detectives rushed to the Hauraki Gulf after a boatie made a grisly discovery — internal organs floating in the water.
But the officers were stood down after the grim find was revealed to be the entrails of a cow.
Senior Sergeant Martin Paget, head of Auckland's Police Maritime Unit, said the remains were spotted off Kauri Point, a 10-minute boat ride from the base, in March.
It is understood the remains included an intestine and a colon.
"We scooped it out of the water and it ended up in a bucket because it was obviously some internal organs of some mammal," Paget said.