WASHINGTON (AP) -- It was a sneak attack, but not by the enemy they feared.
U.S. Army Capts. Joshua Lawrence and Drew Russell were inside a small command post on an Afghan army base, wrapping up a long day of coordinating the safe arrival of nearly 100 Afghan religious and tribal leaders for a peace conference at a nearby palace.
Darkness had fallen.
Some of their fellow soldiers had retired for the evening. Two stood guard.
All seemed well.
But as several soldiers sprawled on nearby cots, playing cards, the calm collapsed catastrophically at 9:27 p.m.
An exploding grenade shattered the stillness, followed in seconds by bursts of gunfire. Before any of the Americans could raise a hand to defend themselves, Lawrence was dead from a bullet to the head, and Russell was dying, shot three times in the back.
They were not killed by the Taliban, as the U.S.-led military coalition indicated the day after the Oct. 8, 2011, assault. Lawrence, 29, of Nashville, Tenn., and Russell, 25, of Scotts, Mich., were killed in what U.S. investigators later called a "calculated and coordinated" attack by Afghan soldiers entrusted to work alongside their U.S. partners.
This is the first published account of the attack and is based on internal Army records and interviews in the U.S. and Afghanistan.
For Russell's family, the anguish is still fresh. His father, Jim, said the loss was even harder to accept after learning from the Army's investigation report early this year that it was a supposed ally, not the Taliban, who killed his son.
"It wasn't like a battle, you know. He pretty much got ambushed," he said, pausing at length to settle his emotions. "That makes it difficult."
On that moonlit Saturday evening, Russell was the designated "battle captain," or duty officer, in the command center. Lawrence worked beside him as a plans officer. Both were members of the 4th Infantry Division's 2nd "Warhorse" Brigade. They deployed to Afghanistan in June 2011. Lawrence had married just one week before leaving; the honeymoon was to wait until he returned home.
The Associated Press learned details of the attack from formerly secret Army investigation records obtained through the Freedom of Information Act. The Army removed substantial portions of the documents to protect what it called properly classified information as well as the identities of most people involved. The AP established some identities on its own.
The investigation -- a standard process in a war zone -- found that security at the U.S.-Afghan command post was so relaxed that guards were not told to check anyone entering. Potential Afghan thievery, not treachery, was judged the chief threat. Thus the killers had unfettered access and moved about without arousing suspicion.
Only 10 designated Afghan security personnel were supposed to be in the compound, but U.S. guards were given no access roster. Unknown numbers "freely entered and exited the compound unchecked," an Army investigator found.
The Americans had been told to treat the Afghans as if they were mingling in Iron Horse Park, a recreation area on their home base, Fort Carson, Colo., according to a staff sergeant who was present but whose name is blacked out on his sworn statement to investigators.
The Americans had convinced themselves, 10 years into a war whose successful outcome depended on empowering local security forces, that they could trust their Afghan colleagues. That was a deadly miscalculation in this instance and dozens more in the months that followed as growing numbers of Afghan troops turned their guns on their coalition partners.
As the attacks mounted this year, U.S. officials in Kabul and Washington insisted these were "isolated incidents." They routinely withheld details and, until pressed by the AP, did not publicly disclose attacks in which coalition troops were wounded but not killed.
At least 63 coalition troops -- mostly Americans -- have been killed, by the AP's count, and more than 85 wounded in at least 46 insider attacks so far this year. That's an average of nearly one attack a week. In 2011, 21 insider attacks killed 35.
The attack that killed Lawrence and Russell in the southern city of Kandahar was the 17th of 2011. Breaking it down in detail shows how easily it can be done.
The two officers and five other U.S. soldiers were inside a soft-skinned, tan-colored tent that served as a temporary "tactical command post" on an Afghan army base known as Old Corps Headquarters. Their task was to coordinate a security plan for the three-day peace conference at nearby Mandigak Palace. Their body armor was stacked in one corner, their weapons in another.
Their partners that day included liaison officers from Afghan security services, including the national intelligence agency and the army. The four liaisons excused themselves for the night and left the compound shortly before the attack. They had been working inside the tent and would have been in the line of fire had they stayed.
The Army investigator called this circumstance "worth noting," but he established no proof of complicity by the Afghan security officers.
An Afghan investigation concluded that only one soldier, a sergeant identified as Enayut (Afghans often use just one name) fired on the Americans, according to a summary of the probe, while the U.S. Army concluded there were two shooters.
Several U.S. soldiers recalled noticing two, possibly three, Afghans enter the compound about 9 p.m. They stood out because they were armed with one rocket-propelled grenade and at least one M16 rifle. At least one was wearing an Afghan army uniform, the report said. No one questioned them, since there was no screening requirement in place.
"They just walked in like they owned the place," a U.S. sentry at the compound's barricaded entrance told investigators afterward. Like others, his name was blacked out of the report.
In the moments that followed, hints of trouble were obscured by the appearance of normalcy.
At 9:02 p.m., just a few minutes after taking up his guard position at the front entrance of the command post tent, Spc. Paul A. LeVan was told he was being repositioned to a guard tower overlooking the compound. He was not replaced at the tent. There was no explanation as to why.
LeVan's sergeant led him to the empty guard tower, where, as a standard precaution, they discussed the locations of friendly forces in LeVan's line of fire. He was armed with an M249 light machine gun.
Soon, two of the Afghans who had entered the compound at 9 p.m. joined them in the tower. One was in military garb and, rather curiously, armed with a grenade launcher and one grenade. The other was unarmed and spoke English. LeVan's sergeant then left the tower and, upon entering the command tent, mentioned the grenade launcher to those inside, including an enlisted soldier who recalled later that the weapon seemed "out of the ordinary."
"But since (Afghan soldiers) were allowed to carry RPGs (rocket-propelled grenades), we did not give it much thought," the enlisted soldier, whose name was blacked out of the report, told investigators.
Another unidentified soldier said in the report that he, too, noticed the RPG and thought it "seemed reckless" to permit it inside the compound.
In his final report, the Army investigator found it curious that neither LeVan nor his sergeant challenged or questioned the two Afghans about "why a tower guard would have an RPG and no rifle."
LeVan, 21 at the time and a member of the 209th Military Police Company, said he assumed the Afghans were a properly assigned guard and his interpreter, although he noticed that the armed Afghan was avoiding eye contact and closely tracking movements inside the compound. LeVan shook hands with both men, but the veneer of friendliness soon vanished.
"I had a gut feeling that something was out of place," he told the AP in a telephone interview. He was the only American to witness the attack from start to finish.
Suddenly and without explanation the Afghans descended from the tower.
"I got nervous, so I kept a very close eye on the two men," LeVan told an Army investigator two days later.
LeVan said he watched through his night vision goggles as the Afghan armed his grenade launcher and took aim at several Army medics playing cards on cots they had set up at the rear of their armored ambulance. A medic recalled spotting the gunman pointing the RPG at them from point blank range. "I stood up and shouted, 'Hey! What the f--- are you doing?'" she told investigators.
His rocket missed the soldiers and slammed into a nearby concrete barrier. Shrapnel wounded the medic in her stomach and back. A piece of shrapnel also penetrated the nearby command tent, wounding the U.S. sergeant who had just left LeVan in the guard tower.
By several accounts, bullets began flying about five seconds after the grenade exploded.
"The timing was perfect," LeVan recalled. He watched from the tower as another gunman -- not the one who launched the rocket, and not the English-speaking Afghan, either -- advanced swiftly on the command tent, firing bursts from an M16 semi-automatic rifle.
Inside the tent, which was ringed with sandbags but filled with dust from the grenade blast, Lawrence and Russell hit the ground and began low-crawling side-by-side toward their body armor.
Neither would get back to his feet. The M16 shooter fired a total of 14 bullets into the tent, the last few from the front entrance. None of the Americans inside saw their attacker well enough to identify him.
"I saw someone standing in the entrance to the tent shooting at all of us," said the sergeant who had been hit in the leg by shrapnel. "I put my head down. I believe I heard five or six rounds fired, and then the shooting stopped."
Maj. Keith Walters, who was in the tent and suffered a severe leg wound from the M16 fire, said that by the time the gunman vanished it was too late.
"As the firing stopped, I remember yelling out to hold fire as I knew we had friendly U.S. and Afghan forces somewhere in the compound and that by then they would probably be approaching the tent. We did not return a single shot," Walters wrote in an email to investigators three weeks later from his hospital bed in Washington, where he underwent surgery.
Walters' unit, the Army's 4th Infantry Division, denied an AP request to interview Walters, saying the matter was too sensitive; later it said Walters had decided on his own not to be interviewed.
Lawrence apparently died instantly of his head wound. Russell was declared dead a short time later at a nearby helicopter landing zone as colleagues prepared to evacuate him and three seriously wounded soldiers to medical facilities at Kandahar Air Field.
Four other soldiers were wounded less severely.
The killers escaped -- apparently with inside help. They remain at large.
Gen. Jallaad Rahimi, who was the chief military prosecutor in Kandahar at the time, told the AP in a recent interview that the father and brother of Sgt. Enayut, plus three of his fellow soldiers, are in detention. The three soldiers are not accused of shooting anyone but are charged with neglecting their duties or assisting Enayut, Rahimi said. For example, the rocket-propelled grenade fired by Enayut was assigned to a member of his unit who told investigators that Enayut had taken it from him that evening when he was not looking, Rahimi said.
Rahimi said two of the detained soldiers are accused of helping Enayut escape the compound.
Enayut's father and brother were arrested after authorities found evidence at their home that Enayut had been in contact with insurgents, Rahimi said. The brother and the father knew about this contact, Rahimi said, but didn't tell authorities and may have covered up for Enayut. The U.S. investigation found no links to insurgents.
Enayut, 23 at the time of the shooting, joined the Afghan army in 2006. An expert in disarming bombs, he had a history of going AWOL and receiving no punishment for it. U.S. investigators found that he had slipped away for an unauthorized visit to Pakistan just weeks before the attack.
Investigators were unable to pin down identifying information about the other shooter, although it appeared he also was a soldier and was probably a member of Enayut's unit, the 4th Battalion, 1st Brigade, 205th Corps. LeVan said both wore Afghan army uniforms in the attack.
In a two-sentence statement the next day, the U.S.-led military command in Kabul said two service members had been killed in an "insurgent attack." A day later, in identifying Lawrence and Russell as the casualties, the Pentagon reported that "enemy forces" killed them.
The Army's investigation records show that U.S. officials in Afghanistan were told immediately after the assault that it was perpetrated by one or more Afghan soldiers -- not insurgents.
"Yes, we know the shooter," the Afghan army liaison officer told Lt. Col. John Cook, the commander of Lawrence's and Russell's unit, after being summoned back to the compound just moments after the killings. The Afghan officer named Enayut without hesitation.
Asked why its Oct. 9 report was never corrected, the international military command in Kabul said it knew that at least one of the shooters was wearing an Afghan army uniform, "but as that information was unconfirmed, a correction to the original (press) release was not appropriate."
In April the AP was alerted to the attack's true circumstances by an American soldier who knew the real story. The U.S. military in Kabul acknowledged to the AP in May that it had added the incident to its 2011 list of insider attacks. But it refused to provide any details of what happened.
The story of the killing of Lawrence and Russell raises hard questions about the insider attack problem, starting with this: How can it happen to arguably the world's best-trained, best-equipped army? The answer, in this case, is that the Americans designed their security with external threats in mind -- known Taliban tactics like suicide car bombings, for example -- rather than threats from their Afghan allies.
Was that reasonable?
Yes, says Maj. Gen. James L. Huggins, who ordered the internal Army investigation in his capacity as the senior U.S. commander in southern Afghanistan at the time. In rejecting the investigation's central finding -- that U.S. officers had failed to take necessary security precautions -- Huggins wrote that the security arrangements were "appropriate responses" to available intelligence.
"Only (in) hindsight do we now understand the insider threat present at the time of the attack," he wrote on Dec. 17, 2011.
In making that judgment, Huggins overruled the colonel who conducted the investigation. The colonel, whose name was removed from the copy of the report provided to the AP, wrote in his account that the U.S. chain of command in Kandahar "failed to use the appropriate security and force protection measures to secure the compound and safeguard their soldiers."
The colonel faulted the Kandahar commanders for "unchecked reliance" on the Afghans to "police their own ranks." He recommended action be taken against those leaders, but Huggins rejected the advice, saying he believed they had taken reasonable precautions, given that there was "no known insider threat at the time."
Of the 16 insider attacks that preceded this one in 2011, none had occurred in Kandahar province, but two took place in adjacent provinces within Huggins' area of responsibility, according to U.S. records.
Huggins, who now works for the director of the Army staff at the Pentagon and has been selected for promotion to lieutenant general, declined through a spokesman to be interviewed for this story. In a brief encounter last week, Huggins told the AP he could not remember enough about the case to discuss it.
The U.S. military never established a clear motive for the attack in Kandahar. In its aftermath numerous Afghans told U.S. officers they felt shamed by the killings and were sorry for any mistrust it created. But that sentiment apparently was not universal.
LeVan told investigators that the day after the attack he and other soldiers encountered an Afghan soldier who "gave us a vibe that he wished we were killed."
Associated Press writer Rahim Faiez in Kabul contributed to this report.
Robert Burns can be followed on Twitter at http://www.twitter.com/robertburnsAP