The roosters crow at 3 a.m. and then, under skies said to be dusted with poison, the hill people of Laos rise for work in the fields. There are pumpkins, opium poppies, rice and now, says one who knows them well, the red powder "rains" from Communist planes.

The one who knows them well: Jane Hamilton-Merritt, an American photojournalist who has lived on and off with the Hmong and Yao tribes for the past 10 years. First researcher and then chronicler, she has turned friend, artistic patron and lonely voice against what she says is the genocide of these unknown American veterans -- CIA-trained Laotians, once a secret backbone of the U.S. war in their country.

"I really had to do something about it, as a human being," she said recently, "although I must say, in the beginning, the attitude of this government was 'Who wants to hear about another bunch of starving gooks?" Like, 'I've had it up to here with Southeast Asia.'"

As art patron, she has encouraged and brought back the decorative fabrics of the tribal women to galleries in SoHo, Martha's Vineyard and now the China Coast in Georgetown. The show, including her photographs that range from the lush hillsides around Chief Chao Laa's village to the skeletal babies of Laotian refugee camps, has been on view this month.

During an interview at the China Coast, Hamilton-Merritt nibbled on Pepperidge Farm cookies and drank coffee from a delicate, flowered cup as violin music drifted out of the gallery's stereo. At 39, she has a healthy, pink face and blond hair, and she wore a long checked kilt, gray kneesocks and penny loafers. As she talked, the hill people of Laos seemed as far away as the surrounding photographs of them were close.

But then the phone rang, with word from an aide of Rep. Jim Leach (R-Iowa). Hamilton-Merritt has been lobbying Leach, one supporter of her cause, as well as other politicians in an attempt to get a congressional hearing investigating what she believes is chemical warfare against the Laotian hill people. Tallies from the tribes put the number killed by gas in a three-year period at nearly 1,000; another 90,000 have fled as refugees to Thailand.

So far, the State Department has taken a cautious position: A report released last year said poison gas has been used against mountain tribes in Laos, but also said a department investigation couldn't prove reported attacks by Vietnamese and pro-communist Laotian jets.

And in reaction to Hamilton-Merritt's claims, an assistant director of the Arms Control and Disarmament Agency, offered this: "The U.S. position is that we have received many reports of the use of toxic chemicals in Laos, Cambodia and Afghanistan. We think the reports are important enough that there should be some sort of impartial investigation."

Countered Leach: "The State Department is caught in a bind. They don't want to offend our relations with the Laotian government, as minimal as they are. But there is an analogy to Auschwitz. No one in the State Department or the White House actually witnessed what was happening in Germany in the 1940s, but definitive information was available. The same is true of Laos and Cambodia. Jane Hamilton-Merritt is absolutely right. People are being maimed and killed."

All this disillusions Hamilton-Merritt, yet another good-cause person in a town where good-causers are as abundant as red tape. But in her case, the cause runs deep: She considers herself one of the hill people.

"Once I was off on a fishing expedition with them," she remembered, "and I got very sick. Very sick. So they made a bamboo raft for me, with banana leaves for a shelter, and took me down the river to the nearest village. bIt took two days."

Or:

"If you walk up in the hills of Laos, and you see the people in their red ruffs [native costumes] with their babies on their backs, it's just like seeing flowers on the mountain."

Or explaining if she ever thought of marrying into the tribe:

"Like Hope Cooke? [The American debutante who married the king of Sikkum.] No. But I'm sure it danced in my head. I think Hope Cooke found it difficult -- and she was married to the king, don't forget. As for me, I'm just one of them."

She lives in rural Connecticut, wife of an American businessman and pilot she met here on a blind flying date at cherry blossom time. They were married in Bangkok, on Halloween. She visits Laos at least twice a year, but is also a professor at Southern Connecticut State College and a farmer's daughter from Indiana who, after reading Pearl Buck's "The Good Earth" in grade school, decided that one day she would go to the Far East.

The Vietnam War was her chance. In 1965, she left a job teaching English at the University of Dayton. She had a beat-up camera and typewriter, but little money, so she bartered English lessons for rooms; later, her writing and pictures were used by CBS, The New York Times and Bangkok newspapers.

She filed the daily body-count stories, but also found her way into the northern Laotian hills that hold the Hmong and Yao.Their culture fascinated her, making her as curious about them as they were about the American woman who had a camera and said "geez."

But she went fishing and deer-hunting with them, and had special chicken dinners with the village chief's family. His wife always gave her presents when she left.

In 1976, they said to her: We want to tell you something. The rains are falling." Red and yellow powder rains, that made the people vomit and convulse and made some of them die.

So I took up the cause of the tribal people as a cause I couldn't ignore," she shrugged. "What could I do?"