Washington – The Supreme Court tried Monday to inject some mystery into its second consideration of a long-running dispute between Georgia and Florida over water that flows from the Atlanta suburbs to the Gulf of Mexico.

Invoking Agatha Christie and Arthur Conan Doyle, the justices puzzled over Florida’s claims that blame for the decimation of the state’s oyster industry lies with Georgia farmers who use too much water from the Flint river.

By the time the Flint joins with the Chattahoochee river to form the Apalachicola river at the Florida line, too little is left for Florida’s once lucrative oyster fishery.

Georgia says the fault lies with overharvesting of oysters, historic droughts and mismanagement, among other reasons.

Chief Justice John Roberts said many factors could have played a part, comparing the situation to Christie’s “Murder on the Orient Express.”

“A lot of things took a stab at the fishery...But you can’t say that any one of those things is responsible for killing the fishery,” Roberts said.

Justice Clarence Thomas gave the dispute between the two states, and their differing claims about how much water even is at issue, a title in the manner of Doyle’s tales about Holmes, “the case of the disappearing water.”

Florida is seeking a court order forcing Georgia to limit its use of water from the Flint. When the justices first heard the dispute three years ago, Florida also was claiming that the Atlanta area’s consumption of water from the Chattahoochee river also played a big role in the reduced flows in Florida, but that claim has fallen out of the case, Gregory Garre, Florida’s lawyer, said Monday in arguments that were held via telephone because of the coronavirus pandemic.

“I would say in closing it’s hard to imagine New England without lobsters or, say, the Chesapeake without crabs, but, in effect, that’s a future that Apalachicola now faces when it comes to its oysters and other species,” Garre said.

Last year, the Florida Fish and Wildlife Conservation Commission voted unanimously to shut down oyster harvesting in Apalachicola Bay through the end of 2025 because of a dwindling oyster population.

Craig Primis, representing Georgia, urged the justices to end the case in his state’s favor because Florida had not conclusively proved that its northern neighbor is to blame for the problems on the Apalachicola.

Florida’s lawsuit against Georgia was filed directly in the Supreme Court, which is mainly an appellate court but hears disputes between states. The court appointed a special master to evaluate the case, and he initially recommended that Georgia should prevail. But three years ago, the justices voted 5-4 to give Florida another chance to prove its case.

The court appointed a new special master, who also recommended the court side with Georgia. Florida’s objections to that recommendation are at issue in the Supreme Court.

The outcome could come down to the views of the two newest justices, Brett Kavanaugh and Amy Coney Barrett, who were not yet on the court when it heard the dispute in 2018. The justices they replaced, Anthony Kennedy and the late Ruth Bader Ginsburg, both voted with Florida.

Kavanaugh asked similar questions of both sides that made it hard to assess how he might vote. A decision is expected by late June.

Barrett wondered whether Georgia could take some steps without incurring too much expense to help revive Apalachicola oysters. “How do we put a price on an environmental benefit like that?” she asked.