I’ve now watched through glass and bars as 11 men were put to death at a South Carolina prison. None of the previous 10 prepared me for watching the firing squad death of Brad Sigmon on Friday night.

I might now be unique among U.S. reporters: I’ve witnessed three different methods, including nine lethal injections and an electric-chair execution. I can still hear the thunk of the breaker falling 21 years later.

As a journalist, you want to ready yourself for an assignment. You research a case. You read about the subject.

In the two weeks since I knew how Mr. Sigmon was going to die, I read up on firing squads and the damage that can be done by the bullets. I looked at the autopsy photos of the last man shot to death by the state, in Utah in 2010.

I also pored over the transcript of his trial, including how prosecutors said it took less than two minutes for Mr. Sigmon to strike his ex-girlfriend’s parents nine times each in the head with a baseball bat, going back and forth between them in different rooms of their Greenville County home in 2001 until they were dead.

But you don’t know everything when some of the execution protocols are kept secret, and it’s impossible to know what to expect when you’ve never seen someone shot at close range right in front of you.

The firing squad is certainly faster — and more violent — than lethal injection. It’s a lot more tense, too. My heart started pounding a little after Mr. Sigmon’s lawyer read his final statement. The hood was put over Mr. Sigmon’s head, and an employee opened the black pull shade that shielded where the three prison-system volunteer shooters were.

About two minutes later, they fired. There was no warning or countdown. The abrupt crack of the rifles startled me. And the white target with the red bull’s-eye that had been on his chest, standing out against his black prison jumpsuit, disappeared instantly as Mr. Sigmon’s whole body flinched.

It reminded me of what happened to the prisoner 21 years ago when electricity jolted his body.

I tried to keep track, all at once, of the digital clock on the wall to my right, Mr. Sigmon to my left, the small rectangular window with the shooters, and the witnesses in front of me.

A jagged red spot about the size of a small fist appeared where Mr. Sigmon was shot. His chest moved two or three times. Outside of the rifle crack, there was no sound.

A doctor came out in less than a minute, and his examination took about a minute more. Mr. Sigmon was declared dead at 6:08 p.m.

Then we left through the same door we came in.

The sun was setting. The sky was a pretty pink and purple, a stark contrast to the death chamber’s fluorescent lights, gray firing-squad chair and block walls that reminded me of a 1970s doctor’s office.

The death chamber is less than a five-minute drive from Correction Department headquarters along a busy suburban highway. I always look out the window on the drive back from each execution. There is a pasture with cows behind a fence on one side, and on the other, I can see in the distance the razor wire of the prison.

Armed prison employees were everywhere. We sat in vans outside the death chamber for what I guess was around 15 minutes, but I can’t say for certain because my watch, cellphone and everything else were taken away for security, save for a pad and a pen.

Over to my right, I saw the skinny barred windows of South Carolina’s death row. There were 28 inmates there earlier Friday, and now there are 27.

That’s down from 31 last August. After a 13-year pause while South Carolina struggled to obtain the drugs for lethal injections, the state has resumed executions. Inmates may choose among injection, electrocution or the firing squad.

I witnessed Freddie Owens being put to death Sept. 20. He locked eyes with every witness in the room.

I saw Richard Moore die Nov. 1, looking serenely at the ceiling as his lawyer, who became close to him while fighting for his life over a decade, wept.

And I was there, too, when Marion Bowman Jr. died Jan. 31, a small smile on his face as he turned to his lawyer, then closed his eyes and waited.

I remember other executions, too. I’ve seen family members of victims stare down a killer on the gurney. I’ve seen a mother shed tears as she watched her son die, almost close enough to touch if the glass and bars weren’t in the way.

Like that thunk of the breaker back in 2004, I won’t forget the crack of the rifles Friday and that target disappearing. Also etched in my mind: Mr. Sigmon talking or mouthing toward his lawyer, trying to let him know he was OK before the hood went on.

I’ll likely be back at Broad River Correctional Institution on April 11. Two more men on death row are out of appeals, and the State Supreme Court appears ready to schedule their deaths at five-week intervals.

They would be the 12th and 13th men I’ve seen killed by the state of South Carolina. And when it is over, I will have witnessed more than a quarter of the state’s executions since the death penalty was reinstated.