Exclusive: A new documentary about Christo Grozev, an investigative journalist put on a Kremlin “kill list” for exposing Russian assassination plots, will make its broadcast debut on Frontline.

The long-running PBS investigative documentary series produced by GBH in Boston has struck a deal to air the film directed by James Jones the night of May 6 on PBS stations, as well as Frontline’s YouTube channel and the PBS Documentaries Prime Video Channel. The documentary will become available that same evening (at 7 p.m. Eastern/6 p.m. Central) at pbs.org/frontline and through the PBS App. Prior to the Frontline, Antidote will have a limited theatrical release in Los Angeles.

Grozev rose to international prominence by uncovering Kremlin schemes to poison Russian opposition leader Alexei Navalny and Russian British activist and journalist Vladimir Kara-Murza. While that work earned him the sobriquet “rock star investigative journalist,” it didn’t endear Grozev...