For more than a decade, an organization headed by former South Vietnamese military men ran a death squad on American soil — killing journalists, torching businesses, intimidating those who challenged its dream of re-starting the Vietnam War. The FBI spent years trying to build a case, but to this day no one has ever been arrested in what the authorities classified as a multi-state case of domestic terrorism.

ProPublica and Frontline re-opened the investigation, talked to victims and suspects, examined once classified files, uncovered government missteps and won startling admissions. Five members of the organization, known as the Front, conceded the group had run an assassination squad. It even had a nickname: “K-9.”

The ProPublica and Frontline investigation, “Terror in Little Saigon,” will be published and broadcast on Nov. 3.