Two years ago today, Julian Assange had just flown out  of Iceland with the shocking video he’d been working on for weeks in his bag. It showed U.S. helicopter gunships firing on Iraqi civilians on the ground, along with two Reuters staffers, and at least two children riding in a van. Assange had already dubbed it "Collateral Murder."  On April 5, 2010, he would release it to the world.   Here is an exclusive excerpt from the new book (and e-book) I have written with my former assistant here at The Nation, Kevin Gosztola, titled  Truth and Consequences: The U.S. vs. Bradley Manning (Sinclair Books).

The shadowy organization, WikiLeaks, aided by a corps of volunteers, had been leaking sensitive documents for more than three years, but drawn only modest media coverage in the U.S., beyond a few brief flurries, when it: published messages hacked from Sarah Palin’s Yahoo! account; exposed emails between scientists on global warming (which became known as "Climategate"); and released 570,000 pager intercepts from September 11, 2001.

Near the close of 2009, the organization was scrambling for funds. Julian Assange, 38, had pleaded for donations to prepare what he described as hundreds of thousands of pages of documents relating to "corrupt banks, the U.S. detainee system, the Iraq war, China, the U.N," and other topics. A German foundation reportedly collected about $1 million for the WikiLeaks account, easing the way for a busy 2010.

If, in fact, Pvc. Bradley E. Manning came to contact WikiLeaks (anonymously, if at all, Assange insists) during this period, how did it come about? One must rely largely on the "chat logs" that allegedly document the lengthy discussions between Manning and convicted hacker Adrian Lamo from May 21 to May 25, 2010. Little other evidence against Manning surfaced for some time and even the validity of the chat logs had been called into question, both because of what appears there and what had been edited out. The prisoner, of course, was innocent until proven guilty.

With that said, the chat logs suggest that Manning told Lamo that he first contacted WikiLeaks back in late-November 2010, after Wikileaks posted the pager messages from 9/11. By then, he had been probing classified military and government networks for months, and saw that they contained "incredible things, awful things… that belonged in the public domain, and not on some server stored in a dark room in Washington D.C.," he told Lamo.

Then he discovered a graphic video of an attack on what seemed to be Iraqi civilians by U.S. Apache gunships back on July 12, 2007. Perhaps the most questionable aspect of the attack came after a van arrived to take one or more of the badly wounded from the scene, probably to a hospital. Fire from the Apache obliterated the van. "At first glance it was just a bunch of guys getting shot up by a helicopter," Manning supposedly wrote to Lamo much later. "No big deal … about two dozen more where that came from, right? But something struck me as odd with the van thing, and also the fact it was being stored in a JAG officer’s directory. So I looked into it."

When he returned to Baghdad on February 11, Manning went into leak mode — according to the chat logs. He would tell Lamo that in February he transmitted to WikiLeaks the Reykjavik13 cable, which he called the "test document"; the 2007 Iraq Apache video; a video of a May 2009 air attack near Garani in Afghanistan that may have killed almost 100 civilians, including many children; a quarter of a million U.S. diplomatic cables from embassies around the world; and possibly much more.

On April 5, 2010, WikiLeaks posted on its site the Iraq video, now titled Collateral Murder. It showed U.S. Army Apache helicopter air strikes in an eastern district of Baghdad in July 2007, which killed two staffers for Reuters and a dozen or more others. WikiLeaks said it had obtained the video from unnamed "whistleblowers" in the military.

The video drew a massive worldwide audience, quickly reaching millions. Now WikiLeaks had fully arrived — as a concept, as an organization, as a media fixture in America.

Mass attention, but also confusion, greeted the video’s debut. The WikiLeaks site crashed from all the interest and versions showing up on YouTube varied in length (without explanation) and quality. Sound was an issue, since one key aspect was the often crude or celebratory commentary by crew members in the helicopters as they targeted, then destroyed, some of those on the street below. "Look at those dead bastards!" one crew member exclaimed. Some versions of the videos helpfully included verbatim subtitles.

Quickly, a Pentagon official confirmed to Reuters that it was legit. Reuters had been attempting since 2007, under the Freedom of Information Act, to get a copy of the video. According to The New York Times, "Reuters employees were allowed to view the video on an off-the-record basis two weeks after the killings, but they were not allowed to obtain a copy of it." Now the military revealed that it could not even find its own copy of the video.

The shorter tape exposed the first two attacks on that fateful July day. First, the "Crazyhorse 1/8" copter team targeted with 30 mm cannon fire a group of about ten men walking on an urban street, suspected insurgents, more than one possibly carrying weapons, including an AK-47. This was when the two Reuters staffers, Namir Noor-Eldeen (who was holding a camera with a long lens that might have been viewed by some as an RPG launcher) and Saeed Chmagh were hit, the first killed instantly, the other badly wounded.

The second incident involved 30 mm cannon fire aimed at an unarmed Iraqi who had arrived in his van (with the two children in the front seat) to rescue the wounded Chmagh, who was crawling on the pavement. Three died in this assault, including Chmagh and the van driver, and the two kids were severely wounded.

The full video included a third incident a little later on the same day, showing three Hellfire missiles fired into a building by an Apache crew (with the unfortunate code name "Bush"). Several men — some perhaps armed, others unarmed — had been shown entering the building. Some of them, and an unknown number of civilians, including women and children, were reported to have died there.

The mainstream press covered it widely. Elisabeth Bumiller at The New York Times noted that at the time of the 2007 incident the military had cited "hostile" fire in the area. But now she observed flatly that "the video does not show hostile action." Yet a military investigation after the incident had cleared the copter crews and no disciplinary action was taken.

The audio fueled the outrage. "Just, fucking — once you get on ’em, just open ’em up," one crew member advised. As the wounded Reuters staffer crawled on the sidewalk, a crew member practically begged him, "All you gotta do is pick up a weapon," meaning that then he could be fired on again. When it became clear that two children were hurt, someone commented, "Well, it’s their fault for bringing their kids into a battle." When a U.S. vehicle rolled over a dead body, one observer seemed to chuckle.

Hours after the video appeared, the U.S. Central Command released its report on the 2007 incident. It asserted that the soldiers of Bravo Company 2-16 Infantry had come under small arms and RPG fire that morning nearby, forcing the arrival of the Apaches. From there on out the crew adhered to the rules of engagement. The report included pictures of machine guns and grenades it claimed were found near the bodies of those killed. The Reuters employees, it charged, "made no effort to visibly display their status as press or media representatives and their familiar behavior with, and close proximity to, the armed insurgents and their furtive attempts to photograph the coalition ground forces made them appear as hostile combatants to the Apaches that engaged them." But how could men walking in the street a mile from the helicopters effectively display their press credentials?

Fox News interviewed Assange, who said, "it’s likely some of the individuals seen in the video were carrying weapons." In fact, a draft version of the video made specific reference to the AK-47s and RPGs, but then WikiLeaks became "unsure" about it. "Based upon visual evidence I suspect there probably were AKs and an RPG, but I’m not sure that means anything," Assange said. "Nearly every Iraqi household has a rifle or an AK. Those guys could have just been protecting their area."

Talking to Fox, Assange called the assault on the van the most damning part of the video. "I’m very skeptical that was done under the rules of engagement; and if it was legal, the rules of engagement must be changed," he said.

Pentagon chief Robert Gates slammed WikiLeaks for releasing the video without providing any context. It was like looking at a war "through a soda straw… These people can put out anything they want, and they’re never held accountable for it." But Assange countered, "it’s ludicrous to allege that we have taken anything out of context in this video." He called Gates a "liar" and asked the media to "stop spinning."

Greg Mitchell is author of more than a dozen books, including his latest on Bradley Manning, and "The Age of WikiLeaks." He writes daily for The Nation.