ST. LOUIS — Scotland searches for the Loch Ness monster. Tibet tracks the yeti. In Missouri and the Eastern United States, it's the elusive cougar. Reports of the big cat keep popping up from Arkansas to Maine. State wildlife officials take calls, mull over photos, send out dogs. So far, there's no evidence the mountain lion is making a comeback in the eastern US. "It's kind of like chasing ghosts and UFOs," says Dave Hamilton of the Missouri Department of Conservation. This week, however, officials here have come up with their best clue yet that something wild is out there. Although the mountain lion (also known as the puma, panther, cougar, and catamount) still roams Texas and the Rocky Mountains - and a subspecies still clings to survival in Florida - Midwestern and other Eastern states haven't hosted a wild population in decades. But don't tell that to the thousands of people who believe they've seen one. "You and I could sit in any cafe in this state for five minutes and we could find 10 people who had seen a [big] cat," says Keith Sutton, magazine editor for the Arkansas Game and Fish Commission in Little Rock. When he published an article in 1990 saying the state had found no evidence of wild mountain lions, the commission got so many angry calls it had to hire extra people to answer the phones. The most recent evidence includes a Christmas Eve videotape in New Hampshire, a mysterious pelt in Missouri, and, most tantalizing of all, two deer carcasses eaten in the way a wild mountain lion would eat. Around 10 a.m. on the day before Christmas, Maureen Clark was cutting up ham when her nephew, Rory Grant, called her to the kitchen window. They saw a large tawny animal. Ms. Clark ran for her camcorder. By the time she started rolling the film, the animal had moved behind some trees, becoming obscured. State wildlife officials call the tape inconclusive and suggest it may have been a bobcat with an unusually long tail. "We got a very clear view of it," counters Clark, a bear trainer in Lincoln, N.H. "There's no human way that it was a bobcat. I know what a bobcat looks like." Here in Missouri, a committee of wildlife experts called the Mountain Lion Response Team is poring over a pelt found by a deer hunter in November. There's no question it comes from a mountain lion. But that hardly clears up the mystery. Freezer burn suggests the pelt spent time in cold storage. Someone has cut it, apparently intending to mount it. But there's no bullet hole or other mark showing how the animal was killed. And if someone did want to mount the trophy, why did they apparently toss it out the window while driving in south central Missouri? "We're just as curious as the dickens," says Jim Low of the state conservation department. "Missouri doesn't have a great deal of suitable mountain lion habitat. [But] we certainly have an open mind about whether there are wild and free-roaming animals in Missouri." The clearest evidence came last Sunday, when two rabbit hunters in south-central Missouri encountered what they describe as a large cat 10 feet up in a tree, surrounded by their dogs. Suddenly, it leaped onto the ground and ran off. The hunters then found a deer carcass and, the next day with conservation officials in tow, they found another one. Those carcasses, plus plaster impressions of the tracks left in the snow, suggest that a wild mountain lion is loose in the state. "It's a population of one," says Mr. Hamilton of the department. "The origin is a big question mark." GENERALLY, though, most sightings turn out to be bobcats, coyotes, or even dogs, wildlife officials say. Even in those rare instances where the sighting involves a mountain lion, it's invariably someone's pet. Some 55 people in Missouri alone have permits to keep mountain lions. And in at least two recent drug busts, police came across dealers who had captive mountain lions without permits. It's conceivable one has strayed from the Rocky Mountains or Florida, where wild populations still exist. Does that mean a wild population is reestablishing itself? "It's unlikely," says Mary Ratnaswamy, a wildlife professor at the University of Missouri at Columbia. "You need a certain number of individuals to maintain a self-sustaining population." Florida officials are having a hard time maintaining the wild panther population in that state despite federal protection and a few dozen known animals. In the late 1980s, Arkansas got so many reports of mountain lions it hired a Texas expert to track down all the credible reports. If the federally protected Florida panther was making a comeback in the state, officials wanted to take measures to ensure its survival. The tracker and his team of dogs spent three years off and on tromping through Arkansas but found no evidence of a wild population. Even so, reports of mountain lions keep coming in. "I don't see this kind of interest with other species," says Mr. Sutton of the state game and fish commission. "There's just something about that creature that grabs hold of people and makes them hope that they're out there.... But they're ephemeral. There's nothing to hold onto to say, 'aha!' "