Their work, undertaken in large part here last week as the filmmakers gathered for the Academy Awards ceremony, was coordinated with law enforcement officials, who said Monday that they were likely to bring charges against the restaurant, the Hump, for violating federal laws against selling marine mammals.
“We’re moving forward rapidly,” said Thom Mrozek, a spokesman for the United States attorney for the Central District of California. Mr. Mrozek declined to say what charges could be brought against the restaurant, but said they could come as early as this week.
In the clash of two Southern California cultures — sushi aficionados and hard-core animal lovers — the animal lovers have thrown a hard punch.
“This isn’t just about saving whales,” said Louie Psihoyos, the director of “The Cove,” a documentary that chronicles eco-activists’ battles with Japanese officials over dolphin hunting. “But about saving the planet.”
The sushi sting actually began in October, when the documentary’s associate producer and “director of clandestine operations,” Charles Hambleton, heard from friends in the music industry that the Hump, a highly rated sushi restaurant next to the runway at the Santa Monica airport, was serving whale.
Mr. Hambleton, who has worked as a water safety consultant on Hollywood movies like “Pirates of the Caribbean,” created a tiny camera for two animal-activist associates to wear during a monster session of omakase — a sushi meal in which the chef picks all the dishes.
Video of their meal shows the two activists, both vegan, being served what the waitress can be heard calling “whale” — thick pink slices — that they take squeamish bites of before tossing into a Ziploc bag in a purse.
The samples were sent to Scott Baker, associate director of the Marine Mammal Institute at Oregon State University. Professor Baker said DNA testing there revealed that the samples sent to him were from a Sei whale, which are found worldwide and are endangered but are sometimes hunted in the North Pacific under a controversial Japanese scientific program. “I’ve been doing this for years,” Professor Baker said. “I was pretty shocked.”
Serving unusual fish imported from Japan is the hallmark of many high-end sushi restaurants here, and whale meat is often found in Japanese markets, Professor Baker said. But he said he had never heard of it being served in an American restaurant.
Workers at the Hump, which according to its Web site is named after an aviation slang term for the Himalayas, directed questions to a lawyer.
“We’re going to look into the allegations and try to determine what is true,” said the lawyer, Gary Lincenberg, in a telephone interview. “Until we have done that, I don’t have any other comment.”
Professor Baker contacted the National Oceanic and Atmospheric Administration, a marine conservation unit of the Department of Commerce, which began its own investigation, eventually looping in the United States attorney in Los Angeles.
Mr. Psihoyos’s team — a far-flung band of activists who use film making to highlight environmental causes — knew they would be together in Los Angeles for the Oscars, and so sting operations two and three were hatched. On Feb. 28, team members split up between the sushi bar and a restaurant table and ordered sushi and communicated via text message with Mr. Psihoyos, who waited in a car in the parking lot. Mr. Psihoyos served as an electronic envoy between the investigators at the sushi bar, who were witnessing the chopping of fish and whale, and those sitting at a table:
“They’re eating blowfish!” read one of the text messages. “Toro and sea urchin, nothing exciting,” another said. “Whale coming now!”
Next waiters identified a meaty course of whale, referring to it at times by its Japanese name, kujira, at a cost of $60, according to a federal affidavit. (The total bill exceeded $600 for two, with very little sake.)
Last week, several federal agents, including one from the Border Patrol and one who speaks Japanese, joined their team. Once again, the chef and wait staff more than once identified the meat as whale, the affidavit said, and it may have been obtained from a Mercedes parked behind the restaurant.
Armed with a search warrant, federal officials on Friday went searching for evidence from the restaurant, including marine mammal parts as well as various records and documents. The possession or sale of marine mammals is a violation of the Marine Mammal Protection Act, and can lead to a year in prison and a fine of $20,000.
Mr. Psihoyos, a former photojournalist who heads a nonprofit through which he makes his films, said that environmental action is more motivating to him than awards.
“Once you become sensitized to these animals you want to save them,” he said over breakfast Monday, still bleary from his big Oscar night.