 -- The former Marine general tapped to become Donald Trump's secretary of defense has been hailed as an "iconoclastic thinker" and a "warrior monk," but a decorated ex–special operations officer recently remembered him another way: as the commander who, he said, left soldiers "to die" in Afghanistan.

Trump announced retired Gen. James Mattis as his pick for the next defense secretary Thursday, sparking a renewed interest in the blunt-talking Marine's history. The next day, a controversial incident from 15 years ago came under the spotlight in the form of a Facebook post by former Green Beret Jason Amerine, who won the Bronze Star for valor in Afghanistan.

In the post, Amerine told the story of when his Army Special Forces team, along with "scores" of allied Afghan fighters, reportedly was hit by friendly fire in December 2001, just weeks after the initial invasion of Afghanistan. With men seriously wounded, Amerine said his team reached out for rescue to the closest American military installation: a Marine contingent commanded by then-Brig. Gen. Mattis.

Mattis, lacking information about the security situation on the ground and the number of wounded and severity of their injuries, decided against sending a rescue force without more intelligence, according to an account of the incident excerpted from the 2010 book "The Only Thing Worth Dying For" by author Eric Blehm.

"I hear you, but no, I'm not sending a rescue mission," Mattis reportedly told another officer. "We. Don't. Know. The situation."

Amerine wrote on Facebook that Mattis finally allowed his Marines to help but only after an Air Force special operations unit stopped at his installation on its way back from getting the injured soldiers.

"'Fog of war' would rightly have delayed the situational awareness of Mattis, but he also had a major and a sergeant major from our calls from my element, JSOC [Joint Special Operations Command] and the CIA," Amerine wrote. "Mattis had an excuse to delay launching medevac while he gathered the facts, but not the six hours it took for AFSOC [Air Force Special Operations Command]" to come to the rescue with the "same information."

"[Mattis] was indecisive and betrayed his duty to us, leaving my men to die during the golden hour when he could have reached us," Amerine said. The golden hour, emergency responders say, is the small window immediately after a severe injury in which it is critical to get the victim to a medical facility for the best chance of survival.

Amerine, who declined to comment for this report, wrote that an American soldier died around the time he finally reached the installation commanded by Mattis. Altogether three American soldiers were killed. On the day of the incident, the Defense Department told reporters five Afghans also had been killed, but later said Afghan officials reported more than 20 dead. Amerine said on Facebook he suspects as many as 50 really died.

While Amerine sharply criticized Mattis for the delay, others have defended the decision as prudent. Mattis has not spoken publicly about the incident, and Blehm told ABC News that Mattis declined requests for comment on it before the book's publication in 2010. Through representatives, Mattis also declined to comment for this report.

Bing West, a veteran and military author who interviewed Mattis multiple times for an upcoming book, said the whole story is "really unfair."

"I understand that Amerine is very angry, but holy smokes," West told ABC News.

He said that there were separate chains of command with regard to special operations and conventional forces and that Mattis was not given operational control over the incident with the Army Special Forces.

A former Army Special Forces officer, who has spoken with other officers who were involved in the 2001 incident, backed up Amerine's complaint and said West's point is largely irrelevant

"That is a horrible answer. Opcon [operational control] or not, a distress call is a distress call, especially with wounded Americans in a combat zone," the officer said in an email. "[Mattis] would have authority to direct his forces to assist."

But even if Mattis had the authority to do something, West said, "Mattis asked fundamental questions that couldn't be answered."

Jack Murphy, a former Special Forces soldier, likewise said that Mattis may have made the right call based on the scant information available. He said it was "curious" that Mattis and the officers who approached him face to face to request assistance for Amerine and his men were apparently not told whether the Special Forces team remained under fire — which would drastically change the kind of rescue mission that would be launched.

"They should've had that basic information," said Murphy, now the editor-in-chief at the special operations news website SOFREP.com.

A source who was briefed on Mattis' version of events said the initial information that came in was conflicting both about where exactly the injured men were and what the security situation was on the ground. "They did everything they could, when they could," the source said, adding that the incident would have come under review for Mattis' various promotions through the military.

Murphy said that, regarding rescue operations in general, "at the end of the day it comes down to the commander" to decide whether to endanger more troops at any given time.

"There's no right answer. The guy on the ground has to make these kinds of assessments," he said.

Murphy said any service member who has been in combat knows the frustration of waiting for even a minute longer than you believe you should have to for a medevac, with your friends' lives on the line.

"The guy's literally dying, and now there's a ticking clock. You're taking care of him as best you can, but you've got to get him back to a hospital," he said. "A story like this really touches a nerve."

The military's U.S. Central Command conducted an investigation into the initial friendly fire incident. Though investigators interviewed the helicopter crews involved in the rescue, the report did not touch on the purported controversy over the response. In a transcript of one interview, an investigator mentioned as an aside that it "took a while for the helicopters to get there."

ABC News' Luis Martinez contributed to this report.