The influential television cop shows of the 1990's, with their jittery, handheld camera work and fragmented story lines, were made to look like the cinéma verité documentaries of the 80's, whose style was made possible by the development of extremely light, portable video equipment.

With "Presumed Guilty," a documentary produced by the San Francisco public television station KQED and directed by Pamela Yates, the process comes full circle. Following half a dozen public defenders and their clients through the San Francisco court system, "Presumed Guilty" makes compelling viewing. But it is viewing of an eerily familiar kind, almost as if the real-life lawyers in the film had patterned themselves on television archetypes.

Phoenix Streets, a smooth, self-assured African-American in his first year on the job, might almost have been studying Blair Underwood's moves on "L.A. Law." Another rookie, Michele Forrar, a lanky young woman from a privileged background in Sacramento, celebrates a courtroom victory by going to the bar she describes as "our `Ally McBeal' hangout." And Stephen Rosen, a senior felony attorney, has the requisite bow tie and bristly mustache; in a series, he'd be played by William Daniels.

The film's two most intriguing personalities aren't so easily classified. Jeff Adachi, the second in command at the Office of the Public Defender, is a fourth-generation Japanese-American whose parents and grandparents were held in a government internment camp during World War II; for him, personal freedom and institutional justice are not abstract issues. Will Maas, who specializes in rape and murder cases, is a thorny, tortured figure who suggests Dostoyevsky more than prime-time television. A recovering alcoholic still grappling with the traumatic experiences of three tours of duty in Vietnam, Mr. Maas spends his sleepless nights talking to a camera, confessing his most intimate self-doubts and anxieties in the form of a video diary.

The most dramatic material in the film comes from Mr. Maas's late-night sessions. Shouting, sobbing or grinding his teeth, he appears to be working out his own sense of culpability by identifying with his client, a Mexican immigrant accused of killing of hair stylist. By saving his client from a life sentence, he seems to hope to save himself.

Mr. Maas's story escapes the formulaic confines of television drama, while much of "Presumed Innocent" seems all too eager to stay within them. Ms. Yates has departed from a strict chronology to rearrange her material for maximum dramatic impact, withholding information to generate suspense and cross-cutting between events to give the appearance of simultaneity when, in fact, they are separated in time. None of this is exactly dishonest, but it does seem a little fast and loose.