Santa Fe D.A. Plays Down 'Rust' Sabotage, Not Sure How Live Ammo Surfaced

The D.A. heading up the investigation into the fatal "Rust" shooting seems sure of one thing, but says the biggest mystery remains unsolved -- how live ammo ended up on the set.

Santa Fe County District Attorney Mary Carmack-Altwies talked to 'GMA' Wednesday to answer about the ongoing investigation into how Halyna Hutchins ended getting shot and killed, and had to admit she still doesn't have much clarity about the live ammunition.

However, she did acknowledge there were multiple live bullets -- beyond the one that killed Halyna -- found on set ... just one of the "Rust" conditions she found alarming.

One thing she did appear ready to dispel was the notion that sabotage might've been at play -- a theory floated by head armorer, Hannah Gutierrez-Reed's, own legal team just a week ago.

Check out how the D.A. responds ... while she says there's no evidence thus far to suggest anything like that occurred, Carmack-Atlwies doesn't completely rule it out as a possibility -- nor does she look the other way on what potential sabotage could mean criminally.

Indeed, if the evidence supported any sort of purposeful intent behind bringing bullets on set and/or mixing them into the box of dummy rounds Gutierrez-Reed dipped into to load Alec Baldwin's gun ... the D.A. says a higher murder charge could be on the table.

Like she noted the last time she held a press conference ... no one's off the table at this point as far as possible charges, and she reaffirms here.