Greg Brooks’ six-year odyssey to salvage a World War II-era shipwreck off Cape Cod has ended, without the platinum or gold he’d hoped to retrieve from the ocean floor.

“Although (Sea Hunters, Brooks’ company) very much wishes to proceed with its salvage project, it acknowledges that at present it lacks the resources to do so or to continue litigation,” wrote Marshall Tinkle, the attorney for the treasure hunter from Gorham, in a brief filed Tuesday in U.S. District Court to abandon salvage of the SS Port Nicholson. Brooks initially claimed that the ship was carrying an estimated $3 billion worth of treasure when it sank in 1942.

Tinkle also filed a motion to withdraw as Sea Hunters’ attorney because the company “has been unable for some time to comply with its agreement with counsel with respect to fees and expenses in this matter.”

Brooks and his crew spent numerous seasons at the Port Nicholson salvage site, but never recovered anything of value. Several other salvage efforts by Brooks dating back to the early 1990s also have been unsuccessful.

In a court filing last December, Brooks acknowledged that research documents discovered by his longtime researcher Edward Michaud and submitted as proof of treasure aboard the Port Nicholson had been faked. He claimed he had no prior knowledge of that fact.

He and Michaud, of Framingham, Massachusetts, are the subjects of criminal investigations but neither has been charged.

What happens next to the SS Port Nicholson is up to a federal judge.

A group of Brooks’ former investors, led by Daniel Stochel of New York, has filed an intervening claim seeking salvage rights over the shipwreck.

“The reprehensible conduct of Sea Hunters and its principal Greg Brooks has earned whatever censure this honorable court deems appropriate under the circumstances, but should not include a termination of this case,” Mission Recovery’s attorney, Seth Holbrook, wrote Tuesday.