On March 21, a Multnomah County grand jury ruled that the Feb. 9 police shooting that killed Portland teenager Quanice Hayes was justified.

This week, the Multnomah County District Attorney's Office released 509 pages of testimony given to the grand jury—including the words of Portland Police Officer Andrew Hearst, who shot Hayes twice in the torso and once in the head with an AR-15 rifle when the black 17-year-old reached for his waistband. (A fake gun was later found next to Hayes' body.)

Hearst is a seven-year veteran of the Police Bureau who has pulled the trigger before in a fatal shooting: the 2013 killing of a mentally ill man named Merle Hatch, who charged officers carrying a broken phone. On Feb. 9, Hearst was assigned to provide "lethal cover" as he and fellow officers pursued Hayes, a suspect in a robbery and carjacking.

In this excerpt from the transcript, Hearst describes the final moments before he shot Hayes, as the teenager crawled out of an alcove outside a Northeast Portland home.

Andrew Hearst: As he has crawled out, I have also stepped out of the flower bed and am now also in the driveway right in line with him. And we start telling him, "Now you are going to go down to your face. Hands out in front of you. Slowly go down to your face."

As he does—as we give those commands, I start noticing that he's looking around. And I perceived it as either he's—you know, this is the final moment. He knows he's about to go into handcuffs. At least that's my perception.

So when he's looking around, I'm thinking either he is looking for an avenue of escape to run or he's looking at a target, an officer, to shoot.

And as he's doing that, he takes his right hand and he drops it to the small of his back. But immediately, as he kind of puts it down, he pulls it back out.

It's like a fluid motion. And it just took my breath away. And I just remember, oh, I almost shot you. Do you not realize what's about to happen? I was just reeling from this reality that I almost shot this person.

But the second that that emotion kind of just went through me, in the same kind of fluid movement, once it's brought out front, he reaches to the front of his waistband, and I fired my rifle. I hear it go off three times. Boom. Boom. Boom. And he immediately falls to his face.

Questioner: Do you want to take a break for a moment?

No. I'm good. Thank you.

On the last time that he made that gesture that you just demonstrated for us, would you say that was a casual, an accidental-type motion on his part, or did it appear to be intentional and deliberate, if you could tell?

I perceived it to be very intentional and very deliberate.

And your use of the AR-15 on your part, was that, was that accidental or was that intentional and deliberate?

I knew that if he were to get to his gun, I would not be able to react fast enough before he was able to shoot one of us.

So it was absolutely a conscious decision on my part to defend myself, my co-workers and any citizen that might be behind me from the threat of him getting that gun out and shooting us.

Because you carry the AR-15, did you believe any other officers were in a position to use deadly force at that time, or did you believe that was your responsibility?

I believed it was my responsibility. And I knew that—I was kind of at the front of this team of officers. I don't know of any other rifles present or any other pistols out that could provide that type of cover. I know that was my responsibility.

You didn't, to be clear, you didn't see, as I understand your testimony, you did not actually see a gun in his hand at the time that you pulled the trigger in your rifle; is that correct?

That's correct. I did not see.

And why not wait until you see a gun pointed at you or see a gun?

I can't wait, because if I let him get his hand on his gun, he will be able to pull that gun out and shoot me or my co-workers before I'm able to react to it.

I just—I can't perceive what he's doing, have that go through my thinking process and then make a decision faster than he's able to shoot me.

And how do you know that?

All through the training from basic to advanced, and then seeing it on the street.