Who can forget the shock of learning in late 1980 that four American churchwomen had been raped and murdered by rightist thugs in El Salvador? Americans' revulsion and anger over that brutality loomed over U.S. policy in Central America for the next four years, a prod to the conscience of Congress and a measure of the Salvadoran government's involvement with terrorism.

The concern lasted until five members of El Salvador's National Guard were convicted of murder this past May. For the governments of both the United States and El Salvador, interest in the case apparently ended with that trial, and relations between the two nations have been rosier and rosier ever since. But if Ana Carrigan has her way, the so-called "nuns' case" won't go away anytime soon.

Carrigan, a New York television producer, has chosen to describe the life and death of Jean Donovan, the one woman of the four who was not a Roman Catholic nun, as a way to view El Salvador's wrenching civil war. In part she has succeeded; her account of the day of the murder and of the cover-up that followed are as gripping as a murder mystery.

Documented by several official reports and assorted personal interviews, it is an infuriating tale of government corruption in El Salvador and the insensitivity of doctrinaire bureaucrats in the United States. The State Department had trouble seeing the murders as anything other than a threat to further U.S. military aid against El Salvador's leftist insurgents. Although several individual foreign-service officers worked hard on the case, for the most part the government treated the churchwomen's relatives as an inconvenience, even while thundering for justice.

There is thin, sketchy evidence that high Salvadoran military commanders may have given orders for the slaughter, and slightly more evidence that the highest levels of the armed forces may have organized the cover-up. Since these faint trails appear to lead to the family of the man who is now El Salvador's defense minister, Gen. Eugenio Vides Casanova, they have not been followed and probably never will be. For a detailed look at the case made by those who believe the cover-up was "sanctioned and concealed by the American government," the last part of Carrigan's book is worth reading.

Unfortunately, the rest of the book is so unblushingly reverent toward Jean Donovan and her calling to El Salvador that it could be one of the more cloying chapters in "Lives of the Saints." Like many of the chosen, Donovan allegedly "had the ability to provide solace and joy" even though, according to Carrigan, she was an obnoxious, arrogant, insecure showoff who sneered at anti-Vietnam War protesters and anyone else who was not a conservative Republican.

This was apparently the result of "a childhood that was straight out of the mainstream American dream" and an aimless early adulthood as a corporate accountant who defiantly rode a high-powered motorcycle back and forth to work.

There are so many mystic premonitions and dramatic foreshadowings in the book that it becomes embarrassing. Nearly everyone Jean Donovan knew seems to recall now that she had a divine calling, some incomprehensible drive to go to and stay in El Salvador, and that they tried vainly to talk her out of it.

While a student in Ireland, Donovan met the Rev. Michael Crowley, a priest with a social conscience. Later she began doing volunteer work with the Cleveland diocese because of him and, on seeing a brochure on diocesan work in El Salvador, "she realized that her search was over . . . here in her hand she held her future."

Yet the book somehow kisses off important moments. Fearful about returning to the violence in El Salvador, Donovan prays for two hours and comes out "an entirely different woman . . . she had come of age. She was happy." A Salvadoran who was apparently the love of Donovan's time in El Salvador appears, wins her heart and dies in the space of two pages, leaving Donovan desolate.

Carrigan tells us that Donovan "never did explain the steps by which she arrived at the conclusion of first-world responsibility for suffering and poverty of the Third World," and Carrigan doesn't either. She is also off base on a few historical facts, asserting for example that Salvadoran land reform did not change much, when in fact the ruling families' fury over actually being dispossessed was and is at the root of much death-squad violence.

Perhaps the most disappointing thing about the book is the gauzy view it gives of the motivations, personalities and work of the other three women who died so terribly, Sisters Ita Ford, Maura Clark and Dorothy Kazel. Perhaps their being nuns makes them less accessible to ordinary Americans, but a view of these four remarkable women through less silvery a cloud of virtue might have made the whole book a little easier to accept.