Alec Baldwin says he did not pull the trigger on the gun that accidentally killed cinematographer Halyna Hutchins on the set of the movie Rust in October.

Hutchins, 42, was killed, and director Joel Souza, 48, injured when the gun Baldwin was holding went off during rehearsals for the western on a ranch outside of Santa Fe, New Mexico – a rare filming fatality that sent shockwaves through Hollywood and has forced a reckoning on the use of weapons on set and cutting corners on production safety.

In a promo for the ABC interview, Baldwin’s first since the tragedy, George Stephanopoulos is shown asking the actor to confirm that it wasn’t in the script for the trigger to be pulled. “Well, the trigger wasn’t pulled. I didn’t pull the trigger,” Baldwin says. Stephanopoulos confirms, “So you never pulled the trigger?” to which Baldwin answers, “No, no, no, no. I would never point a gun at anyone and pull a trigger at them. Never.”

Stephanopoulos, in an appearance on Wednesday morning on Good Morning America, described the 80-minute sit-down as “raw” and “intense”.

The journalist described Baldwin, 63, as “devastated” yet “very candid” and “forthcoming”. The actor “answered every question” and discussed Hutchins, meeting with her family, and his account of what happened on set that day. “I have to tell you, I was surprised in many places over the course of that hour and 20 minutes we sat down yesterday,” Stephanopoulos said.

“I’ve done thousands of interviews in the last 20 years at ABC,” he said. “This was the most intense I’ve ever experienced.”

The Sante Fe county sheriff’s office is investigating the shooting, largely focused on how live rounds, which are banned on set, came to be in the gun held by Baldwin.

According to reports, Baldwin believed the gun was empty. He had been handed the weapon by assistant director Dave Halls, who allegedly called “cold gun” as he passed it over. Weapons on set, including the gun given to Hall, were handled by 24-year-old Hannah Gutierrez Reed, a head armorer juggling her second ever feature gig handling weapons with the job of key props assistant.

Asked how he thinks a live bullet got in the gun, which was supposed to be loaded with blanks or dummy rounds, Baldwin said he had “no idea”.

Baldwin also answered Stephanopoulos unequivocally that the accidental shooting was the worst thing that’s ever happened to him: “Yep … yeah, because I think back and I think of ‘what could I have done?’”

An attorney for Halls told ABC News on Thursday morning that her client has maintained that Baldwin did not pull the trigger, and thinks the accident was a “misfire”.

“The entire time Baldwin had his finger outside the trigger guard, parallel to the barrel,” Halls’s attorney, Lisa Torraco, told Good Morning America’s Kaylee Hartung. “[Halls] told me since day one he thought it was a misfire.”

According to an affidavit for a search warrant filed by the sheriff’s office on 22 October, Halls told investigators he did not know there were live rounds in the Colt .45 revolver before he gave it to Baldwin.

An attorney for Gutierrez Reed said the week after the shooting that the armorer had “no idea” how live rounds became present on the set, and blamed producers for an “unsafe” workplace.

The special, Alec Baldwin Unscripted, will air in the US on ABC on Thursday at 8pm ET, and will be available later on Hulu.