To the government, Richard Mitchell was a staff scientist at the Fish and Wildlife Service hired to identify endangered species and set up programs to protect them.

But to big-game hunters, Mitchell was a man who could lead them to remote reaches of China and Pakistan and give them the chance to hunt rare and even endangered species.

Now, hunters who traveled with Mitchell are being questioned by federal prosecutors in Detroit, Milwaukee and Dallas-Fort Worth. The Justice Department is trying to determine whether Mitchell brought animal carcasses into the country illegally and whether he used his position at the U.S. Fish and Wildlife Service for his own benefit. Mitchell's activities also are being probed by Fish and Wildlife's enforcement division as well as the inspectors general of the Interior Department and the Smithsonian Institution.

When the investigation started in 1988, Mitchell was on temporary assignment to the Smithsonian to develop research projects with the Chinese. Throughout the inquiry, the Smithsonian has paid his legal bills: to date, more than $280,000 in congressionally appropriated funds. With another legal bill for $60,000 pending, the Smithsonian now says it has hired outside counsel to assess its obligations to Mitchell.

The federal investigation centers on services that Mitchell performed for hunters while employed by the government. Under the aegis of a nonprofit organization that he operated from his Arlington home, Mitchell accompanied hunters as they stalked their quarry and helped them bring their kills into the United States. In some instances, according to knowledgeable sources, government prosecutors believe the carcasses were brought into the country in violation of U.S. wildlife protection laws. On at least one trip, these sources said, Mitchell had been sent overseas on government business but some of the same expenses also were covered by hunters. In another instance, the same sources said, prosecutors believe Mitchell worked to get the U.S. government to downgrade the leopard and two other species from endangered status in Nepal with the goal of positioning himself to profit from sport hunting in that country.

Mitchell declined to be interviewed for this story. His attorney, Justin Simon, said Mitchell's activities were undertaken for scientific reasons to protect wildlife and that he violated no laws in carrying them out. In regard to the Nepalese animals, Simon said the Nepalese government wanted them downgraded, and Mitchell merely offered to perform a survey required to achieve that goal.

The Smithsonian's association with Mitchell has raised difficult issues for the institution. "I'm not satisfied with where we come out on this," Secretary Robert McCormick Adams said this week.

The Smithsonian opposes the killing of animals known or thought to be endangered, but on at least two occasions while Mitchell was working at the Smithsonian, he participated in expeditions in which animals that were imperiled or whose status is unclear were killed. In 1988, for example, he took sport hunter Jim Conklin to China, where Conklin killed a Tibetan antelope, a species accorded the highest degree of protection by international treaty because it is in danger of extinction.

Conklin, who got his place on the trip by contributing $35,000 to fund Mitchell's research, said he believed that the animal would be allowed into the United States as a scientific specimen for display at the Smithsonian. But Chinese authorities seized the animal. The Smithsonian says it never set out to collect any threatened species and denies knowledge that any was killed.

As the government inquiry continues, Mitchell remains on the job at Fish and Wildlife, part of the Interior Department.

"It's certainly not the policy of the service to go encouraging employees to shoot endangered species, but that's a very complicated area," said Phil Million, spokesman for Fish and Wildlife. "I guess it is gray. That whole area of what can and cannot be done legally is so complicated."

The Hunter's Perspective When Mitchell co-founded the American Ecological Union and applied for nonprofit status in 1984, papers filed with the IRS described the organization's mission as promoting "the ecological welfare of all living species, including mankind." The Safari Club International, a hunting organization, became one of its major supporters, contributing tens of thousands of dollars to fund surveys of animal populations. Federal investigators say Mitchell agreed to coax hard-to-get hunting permits from foreign authorities and give Safari Club members first crack at them. It could not be determined exactly how much money the Safari Club gave.

In July 1987, for example, Safari Club official Don Morgan informed club members of Mitchell's plans to get hunting permits for wild goat and sheep in Pakistan. "Mitchell understands that {the Safari Club} is first and is actively pursuing the acquisition of permits for major trophies for Safari's use," he wrote.

Mitchell's attorney said Mitchell was merely a go-between and the Safari Club overstated his activities on its behalf. "It is advantageous to the Safari Club in terms of generating some enthusiasm among its members," Simon said.

Even before Mitchell developed his relationship with the Safari Club, he was known among some hunters as a friend at Fish and Wildlife who was helpful on questions about whether certain animals could be imported legally. "Absolutely, he was taking the hunter's perspective," said Chris Klineburger, a Seattle-based hunting outfitter. "That's really the only side there is."

Mitchell sometimes offered to help hunters who wanted to pursue exotic animals. Hunter Robert Chisholm said Mitchell wrote to him in 1985 about arranging a hunt for the rare straight-horned or Suleiman markhor, a species of wild goat, in Pakistan. "I can try to arrange a hunt -- but the damn Suleiman markhor is listed as endangered," Mitchell wrote. "We can shoot one but we can't bring it back into the U.S." The markhor is included in the Fish and Wildlife Service list of animals that may not be imported. {See sidebar on this page.}

Many hunters aren't interested in joining expeditions if they have to leave their trophies -- the carcasses -- behind. According to Chisholm, Mitchell told him, "Bob, there are museums that would like to have this animal ... so why don't you get a museum permit {allowing import of listed animals} and then go hunt them?" Chisholm said he never took up that offer.

Harvesting Wildlife Mitchell's premise was that some hunting could help protect threatened species and that fees from hunters could finance conservation measures. He explained this philosophy in an undated proposal submitted to Chinese authorities under the auspices of the American Ecological Union to spend two years -- from 1984 to 1986 -- setting up a sport-hunting program there.

Wildlife, he wrote, "is a valuable resource that can be harvested" each year. Big-game hunting can generate "the necessary revenue to properly manage and propagate these species."

After conducting surveys of wildlife, Mitchell wrote, "we would train Chinese personnel on how to conduct hunts, prepare trophies and accommodate foreign hunters." Mitchell said he would be assisted by Robert Hoffman, a professor at the University of Kansas who is now assistant secretary for research at the Smithsonian.

Sport hunting is an accepted method of raising money for conservation when an animal population is stable, but several scientists and conservationists interviewed by The Post said such programs are not acceptable when a species is endangered or its status uncertain. "It just doesn't make any sense to start a sport-hunting program on a species that you don't know can take it," said program officer Michael Sutton of the World Wildlife Fund, which does not oppose sport hunting in general.

Hoffman said he supports sport hunting for conservation -- but within limits. "If there is a species that is known to be endangered or thought to be endangered, then we do not deliberately try to collect it," he said.

Given that philosophy, the Smithsonian's relationship with Mitchell has dismayed some conservationists. In a November 1988 letter to Hoffman, George Schaller, scientific director of Wildlife Conservation International, wrote: "That at this critical period in the world conservation movement the Smithsonian seems to promote the killing of animals known or thought to be rare should be embarrassing."

Legal Troubles Schaller's rebuke to the Smithsonian was prompted by a 1988 hunt that marked the beginning of Mitchell's legal troubles. Acting on a tip, Fish and Wildlife agents stopped a party of hunters, accompanied by Mitchell, as they arrived at the San Francisco airport from China. The agents confiscated the horns and hides of four big-horned mountain sheep, alleging that the animals were endangered.

The hunters, including former Texas gubernatorial candidate Clayton Williams and his wife, had paid $25,000 each for permits. They maintained that the government had incorrectly identified the animals as endangered. Demanding their trophies back, they applied political pressure at the Interior Department and filed suit in Texas.

Mitchell's division at Fish and Wildlife -- the Office of Scientific Authority -- took the position that the sheep were not part of an endangered species, putting that office at odds with the agency's own enforcement division. And when federal investigators contacted the Smithsonian, Hoffman too disputed that the sheep were endangered, because of where they were shot. He had not examined the animals. But four scientists who are experts on mountain sheep examined the hides and contended that the sheep were indeed endangered.

With its Fish and Wildlife Service split over the identity of the sheep, the Interior Department decided after months of indecision to settle the case. The government returned the horns and hides to the hunters. The U.S. attorney's office in San Francisco declined to sign off on the settlement. In an August 1989 letter to the Justice Department, assistant U.S. attorney Patrick Bupara said he could not represent Interior in the matter "for ethical and moral reasons." He added: "Speaking for myself, I believe the conduct of certain responsible people at the Department of Interior to be appalling."

The decision to settle the Chinese sheep case alarmed enforcement officers at Fish and Wildlife. In a newsletter published early this year by an association of federal wildlife enforcement officers, , the episode was summarized with the warning that it posed "a true threat" to enforcement efforts.

More Hunts, More Problems While the status of the Chinese sheep was being debated, Mitchell led another expedition to China. This time, an imperiled antelope was killed.

The trip was set up through the Safari Club. Conklin and another hunter, Don Cox, agreed to pay a total of $172,000 to finance an American Ecological Union study of Chinese sheep if they could go along on three expeditions. Mitchell's attorney said his client led the trip at the invitation of Chinese authorities, who approved the collection of all animals that were killed.

In a January 1988 letter to Cox, the Safari Club enclosed a list of animals that would be available, including the imperiled Tibetan antelope and the endangered Chinese mountain sheep. The letter asked Cox to indicate "each animal you want ... so that we may give Dr. Mitchell some lead time."

The expedition was successful but about a week before the group was to leave the area, Chinese authorities ordered them out. "We had these animals all skinned and dried," Conklin said. "{But} we were told we're not allowed to take the trophies out of the country."

Conklin decided to stop funding Mitchell's study. But early in 1989, Conklin said, Mitchell called, asking for money to fly Chinese scientists to the United States for a study program. Still smarting over the loss of his trophies, Conklin applied some leverage. "I said I would make a donation to the Smithsonian of $3,500 if those gentlemen would arrange for the export of the animals that we took," Conklin said. He sent a check to the Smithsonian.

Conklin said he saw a telex from the Smithsonian advising the Chinese that the airfares would be paid if the animal carcasses were released. But months later, he had heard "absolutely nothing from anybody," so he called Mitchell. "Two days later, I received my check back, uncashed, {with a note from the Smithsonian} saying, 'Thank you, Dr. Conklin, for your contribution, but we don't need this money now.' "

The Smithsonian acknowledges returning Conklin's check. The institution has returned money on occasion when it determines that keeping the funds is not in its interest, said spokeswomen Linda St. Thomas.

Hoffman said this week he wished he had known more about Conklin's trip to China, but said he wasn't familiar with details of the expedition -- although he acknowledged that members of the Smithsonian staff were present. Hoffman did have firsthand knowledge of an earlier expedition. Government investigators now believe that animals killed on that earlier trip may have been taken from China without valid export permits.

In August 1987, when Hoffman was director of the Smithsonian's Museum of Natural History, he accompanied Mitchell and hunter Don Cox to China. Cox killed two gazelles and a blue sheep, which were brought back into the United States and logged into the Smithsonian's collection. According to Hoffman, the institution kept only the gazelles' genitalia; the horns and hides were given to the hunter for display.

When government prosecutors later questioned whether Cox had a role in bringing various animals into the United States without valid export permits from the countries of origin, Hoffman reportedly contacted the Chinese about issuing export permits after the fact. The Smithsonian confirmed that government investigators have asked for "a document prepared by Dr. Hoffman" but Hoffman declined to say if this was the request to the Chinese. Through his lawyer, Cox declined to be interviewed for this article.

Thrill of the Hunt Conservation and sport hunting have a close but uneasy relationship. In some circumstances, experts say, sport hunting may help stabilize animal populations. Mitchell's lawyer argues that his client's activities raised a great deal of money that was used for conservation.

But some hunters who supported Mitchell's scientific pursuits acknowledge that they were in it for the thrill of the hunt. Conklin, a Pittsburgh plastic surgeon, donated money to finance a study but said his goal was to hunt in parts of China that had long been closed to Westerners; he would have gone with "anybody that would have the influence" to get him permits from Chinese authorities, he said.

In this case, Mitchell was the man who could get the permit. Zoologist Valerius Geist of the University of Calgary, an expert on mountain sheep who is critical of Mitchell, said it was natural for hunters to be tempted by Mitchell's package deal. "You had as your closest buddy a scientist who goes on the hunt and he is out of the very office that writes the import ... permits and he has the backing of the Smithsonian," Geist said. "Isn't that terrific?"