New footage from an upcoming documentary series offers a look behind the scenes during the deadly 1993 siege of the Branch Davidian cult compound in Waco, Texas.

And it reveals some chilling words from the cult’s leader, a self-proclaimed prophet named David Koresh.

“They think I’m the son of God,” Koresh says in old footage in the trailer for the upcoming Netflix series, “Waco: American Apocalypse.”

Federal agents attempted a raid on the compound on Feb. 28, 1993 after an eight-month investigation found the cult had stockpiled a massive arsenal of weapons.

Four agents and six cultists were killed in the resulting shootout. That kicked off what would turn into a 51-day siege of the facility, and the frantic negotiations to try to end it are detailed in the new documentary.

But a recorded voice ― presumably that of Koresh, speaking to negotiators ― indicates the cultists had other plans.

“OK, y’all been preparing eight months for this,” the voice says. “How long do you think we’ve been preparing?”

The siege ended in tragedy on April 19, 1993 when the FBI tried to clear the compound with tear gas. Instead, the cultists set fire to the facility. In the events that followed, 76 cultists including Koresh and some two dozen children died.

The three-part Netflix series, which premieres March 22, is built around “recently unearthed videotapes filmed inside the FBI’s Hostage Negotiation Command Post, as well as raw news footage never released to the American public, and FBI wiretap recordings.”

It also includes interviews with surviving cultists, FBI negotiators and members of the ATF team who took part in that initial shootout.

“The details of what happened during the 51-day standoff are complex and often ferociously debated, but rather than assigning blame or pointing fingers, we tried to treat it from a deeply humanist perspective — focusing on what it feels like for people on all sides to be caught in the maws of history,” director and executive producer Tiller Russell said in a news release.