Two more protected green sea turtles on O'ahu's North Shore became objects of investigation as the state continued to search for whoever it was who killed a third turtle, apparently for its meat, at Laniakea Beach.

A large dead turtle that was in an advanced stage of decomposition and a young live turtle suffering from tumors were recovered from North Shore beaches yesterday and Sunday, respectively.

Initial reports suggested that the large turtle was a victim of a shark attack but experts determined that it had been struck by a boat propeller.

"Propellers create very distinctive slashes on the turtle," said George Balazs, head of the Turtle Research Program for National Oceanic and Atmospheric Administration. "When it's a propeller injury there's no mistaking it with anything else.

"There's no evidence whatever of a shark attack," Balazs said. "The turtle has been hit by a boat. Of course we never know at this stage of decomposition if the turtle was hit by the boat first and died or if it died from some other unknown cause and then was hit by the boat."

Balazs said there was no evidence of butchering or human tampering on the carcass of the decomposed turtle carcass.

On Saturday, beachgoers discovered the partially buried carcass of "Honey Girl," apparently slaughtered for meat.

The state Department of Land and Natural Resources is looking for anyone with information about the killing of the 200-pound, 30-year-old turtle, said DLNR spokeswoman Deborah Ward.

Green sea turtles are protected by the federal Endangered Species Act as well as Hawai'i state law. As with monk seals, people must keep their distance from the animals or face charges, Ward said.

It is illegal to kill the animal for any reason, she said. "People are not supposed to be swimming near them and following them, which could be viewed as harassment.

"You can enjoy them but don't be sitting on them or grabbing them while they're swimming," she said.

Honey Girl's belly shell and one flipper had been cut off, according to Patrick Doyle, project coordinator for Malama Na Honu, a volunteer group that provides educational information and protection for the turtles at Laniakea Beach.

Doyle said he found organs in the water and Honey Girl was buried in the sand up to her top shell.

Many people had offered condolences but no one seemed to have any information about her death, he said, adding that people are talking about a permanent memorial at the beach.

A makeshift memorial with her photograph was set up at the beach, Doyle said.

"About an hour ago our largest turtle, Kuhina, hauled up out of the water and climbed right up onto her memorial site in front of her picture and has been resting here for an hour now," he said yesterday afternoon.

Honey Girl's remains were taken to NOAA for a necropsy and results are expected by tomorrow, said Balazs.

A third sea turtle was found Sunday suffering from tumors that had left the young animal weak and emaciated, Balazs said.

The 37-pound turtle is under a veterinarian's care and is suffering from tumors in the throat, he said, adding that a decision about whether to euthanize the animal hasn't been made.