Frontline’s film, “Terror in Little Saigon,” and the accompanying ProPublica article, revisited a painful chapter in the Vietnamese-American experience. Since publication, we have heard from many viewers and readers who expressed deep gratitude for our reporting on the murders of five Vietnamese-American journalists and a broader pattern of violence within the refugee communities that grew up in America after the Vietnam War. The film and article showed that the FBI came to believe that an organization started by former South Vietnamese military officers, the National United Front for the Liberation of Vietnam, was linked to the violence.

Over the last week, we have also heard criticisms, in particular from a Vietnamese-American advocacy group called Viet Tan. Viet Tan, whose founders were leaders of the National United Front, has asserted that our reporting failed to prove the connection between the organization and the violence, and was, in certain respects, culturally insulting to Vietnamese Americans. Viet Tan maintains that the National United Front, known most commonly as the Front, was a group committed to fostering political change in Vietnam, and that it has been the target of rumors and false allegations for years.

ProPublica and Frontline’s reporting included an unprecedented examination of the local police and the FBI investigations into the murders in California, Texas and Virginia. The police and FBI files had been secret for decades until we obtained them through the Freedom of Information Act. Now the American public, including the Vietnamese-American community, can begin to assess the substance and shortcomings of years of investigation. For the families of the victims, this was the only opportunity they had been afforded to take stock of what investigators had uncovered and theorized about the deaths of their loved ones. Those investigative files show that FBI agents were persuaded that the Front was behind a campaign of murder, arson and beatings, and they capture the frustration of investigators in never managing to bring any of the perpetrators to justice. As well, five former leaders of the organization told us the group had run its own assassination unit to deal with its critics or suspected Communists.

Viet Tan has also asserted that one or more former Front members who appeared in the film and article were either misquoted or somehow otherwise misrepresented. No one featured in the film or article has contacted us making such a claim. Viet Tan says that one former Front leader, Nguyen Xuan Nghia, now insists he never told our reporter, A.C. Thompson, and director, Richard Rowley, that he had been in a meeting with Front members who talked about killing a newspaper publisher. We would be happy to respond directly toNghia should he want to raise an objection with us.

Viet Tan says that the Front never ran an assassination unit. The FBI’s files, however, are laden with discussions of the Front and the unit, known as K-9 — its suspected members and its catalogue of victims. These entries were built on in part accounts from former members of the Front. Katherine Tang-Wilcox, a retired FBI special agent who helped run the investigation of the Front, said it plainly, in the film and in the article: “K-9 was established as the assassination arm of the Front.”

Viet Tan asserts that there was a preconceived narrative for the reporting behind the film and the article, and it claims that our work was insulting to the wider Vietnamese-American community. Vietnamese patriots, it says, “are relegated to being vengeful veterans motivated by a loss of social status.”

ProPublica and Frontline followed the reporting where it took us. Where it took us over and over again was to the Front. We in no way sought to demonize Vietnamese refugees, and the profound hardships they endured both during the war and in the exodus after. We exposed the work of extremists, and the facts are the facts: Although there may have been other aspects to the Front, it was founded with the express mission of toppling the Communist regime in Hanoi, and it raised money in the U.S. to mount such an effort. It created a makeshift fighting force and tried three times to get inside Vietnam. That such an effort would have held appeal for many displaced and traumatized refugees from a lost war is no surprise. It just happenedto violate American law.

It’s worth noting that we spent time with veterans of the former South Vietnamese military during the course of our reporting, at the cemetery on Memorial Day, at cafes, at their homes, and we are grateful to them for sharing their time with us. Two associate producers on the project, filmmaker Tony Nguyen and Jimmy Tong Nguyen, a translator and veteran of the Army of the Republic of Vietnam, helped in our reporting and our understanding of the appropriate historical context and cultural sensitivity.

In 1993, several Front leaders brought a libel lawsuit against Vietnamese-American journalists who had accused them of being behind acts of violence within the community. Viet Tan suggests that any reading of that case would support the idea that, in fact, the Front was not behind any violence. The claim by the Front plaintiffs that they had been libeled was rejected by a jury.

The story of a long-forgotten and unsolved spate of politically motivated murders and attacks may not have been the story Viet Tan wanted published nationwide, and indeed it is a grim, unresolved chapter in a vibrant community’s rich history. But that is the story told by documents, investigators and interviews in the Vietnamese-American community itself. During our interviews, we were frequently told about additional violence that had never been reported to the FBI, and since the film and articles were published, we have received numerous notes from viewers and readers who want to share accounts of being similarly threatened and harassed.

Over the last week, our journalists have talked about the project in numerous interviews — including in the Vietnamese-American media, where these murders and violence are being passionately debated. We hope the reporting we’ve done can now lead to a break in these long cold cases. There is no statute of limitations on murder, and as Tang-Wilcox, the retired FBI agent, said, “Somebody knows who’s responsible for each and every one of these acts.”