The calmness in his voice gave no hint he’d just killed four people whom he describes as both innocent victims and casualties of war.

At times, Brian Nichols sounded almost meek Tuesday as he justified to police his March 11, 2005, Fulton County Courthouse killing spree as a slave rebellion in which he was a “noble soldier.”

In a three-hour videotaped confession played during his trial, Nichols is shown sitting across a table from an Atlanta Police Department homicide detective, detailing each of four fatal shootings. The dramatic account is the first public revelation of Nichols’ own words —- what he was thinking, or not thinking, as he pulled the trigger.

Nichols is charged with killing Superior Court Judge Rowland Barnes and his court reporter, Julie Ann Brandau, in Barnes’ courtroom, where Nichols was to be tried on rape charges later that day.

He is also accused of killing Fulton County Sheriff’s Deputy Hoyt Teasley on the street outside the Fulton County courthouse, and, later the same night, U.S. Customs agent David Wilhelm in Buckhead.

The confession and the confessor captured on the tape go to the heart of the prosecution’s case —- that Nichols was a methodical and ruthless killer —- and to the defense contention that Nichols was insane when he went on the rampage.

Wearing a T-shirt, sipping on a canned soft drink and addressing his questioner —- homicide Detective Vincent Velazquez —- Nichols opens his commentary almost apologetically.

“Let me just start by saying that, you know, I give my condolences to all the families of those who were killed, um, in combat,” he says.

As the investigator prods, he explains he was provoked to start a “war” on the U.S. government in the courthouse that morning because of a “multitude of different things,” including conditions in the Fulton County Jail and the prison system in Georgia,

“Prisoners are required to work for free,” he says. “You really have no choice other than to work … it parallels significantly the treatment of slaves.” He adds: “I felt as though I was a slave with them. As a soldier, I don’t feel like I committed any war crimes. There was no collateral damage.”

But what finally triggered him to overpower Deputy Cynthia Hall in a holding cell, escape from custody and kill Barnes and Brandau in the courtroom was the feeling that morning that he was going to be convicted of rape and sentenced to prison for the rest of his life.

“I didn’t think it was going well,” he says. “I think the prosecution had the advantage of knowing what our case was.” He says: “The charges I was facing carried two life sentences —- and I didn’t kill anyone.”

He said he realized then “if I was going to die in prison, I felt that possibly I could use my talents to do something noble, and I thought a slave rebellion was noble.” That rebellion started by almost beating Deputy Hall to death.

He tells Velazquez he knows Hall didn’t die: “She did resist and I’m glad she is going to pull through,” he says.

Nichols sounds confused or conflicted at times during the confession as he recounts killing Barnes and Brandau, shooting each in the head once in Barnes’ courtroom as they were hearing a civil case scheduled before Nichols’ trial that morning.

Nichols did not mention the race of any of his victims —- Barnes, Brandau and Wilhelm, all of them white, or Hall and Teasley, like Nichols, African-Americans.

He first describes it this way: “I engaged the target, which was Rowland Barnes. And, um, I engaged the secondary target, which was his court stenographer.”

A few minutes later on the tape, he tells the investigator, “I hope I don’t sound cold,” but the judge was just a casualty of war, and “there is a great deal of honor in anybody who is such a casualty.”

He describes Barnes as a fair judge —- “a good person and he had a good heart.” Barnes and Brandau, he says, “weren’t victims of a crime. They were casualties of a slave rebellion.”

After first describing Brandau as a “secondary target,” he later says he “didn’t actually realize I shot her until there were reports on the news about it. I have no conscious recollection of that.”

Again and again, Nichols says he “spared” the people he encountered in the 26 hours he was on the run by not killing them, including Ashley Smith (now Robinson), whom he held hostage at her Gwinnett County residence for almost seven hours before letting her go. She then turned him in.

He said he killed Wilhelm because Wilhelm identified himself as a federal agent, making him someone with whom Nichols was at war, not a “civilian.”

Prosecutors tried to establish during testimony Monday that Wilhelm was not holding a gun when Nichols shot him. But Nichols says in his confession that Wilhelm did have a gun.

“I was able to take out the target, prior to him actually firing his weapon,” says Nichols. “He identified himself, um, and I just, I was just quicker.”