The trial of three alleged American mercenaries in Afghanistan was a sham from the start.

After six days of testimony in Kabul's National Security Court, the men and several Afghan cohorts were convicted last week of running their own vigilante war on terrorism by illegally detaining and torturing Afghan civilians in a private jail.

If you believe the Afghan prosecutors, the men were out-of-control bounty hunters obsessed with capturing terrorist leader Osama Bin Laden and collecting the $50 million reward on his head.

The defendants, on the other hand, claim the Pentagon and the CIA first approved their covert operation and then abandoned them in the aftermath of the Abu Ghraib prison scandal in Iraq.

Jonathan Idema, 48, a former Green Beret and the leader of the group, and Brent Bennett, 28, were sentenced to 10 years in Afghanistan's notorious Pulcharkhi prison, while Edward Caraballo, 42, an Emmy-winning journalist from the Bronx, got an eight-year sentence.

At the trial, Idema and Bennett insisted that the office of Lt. Gen. William Boykin, the deputy undersecretary of defense for intelligence, initially had approved their actions.

Caraballo, on the other hand, claimed he was just tagging along with Idema and Bennett to do a documentary film on the war on terrorism.

Given that Afghanistan barely has a functioning legal system, the courtroom proceedings hardly qualify as a fair trial.

The prosecution's witnesses, for one thing, were not required to testify under oath, nor were defense lawyers allowed to cross-examine them. The accuracy of courtroom interpreters was repeatedly challenged by the defense.

Then there were the tapes.

Idema and Caraballo produced audio and videotapes, as well as 70 pages of documents. Some of the material appeared to contradict key portions of the prosecution's case. Yet the three-judge panel refused to admit most of the material into evidence. Outside the courtroom, lawyers for the men made the tapes and documents available to reporters.

Some of the film footage shot by Caraballo shows them arriving in Kabul from India on April 14 and being greeted by top Afghan officials - contradicting prosecutors' assertions that the defendants entered the country illegally.

Pentagon officials said immediately after the men were arrested that our government had no knowledge of their activities. But in late July, an Army spokesman admitted that Idema had handed over a suspected Taliban member to officials at Bagram Air Base on May 3.

But the most sensational evidence Idema produced were several videotapes of telephone conversations he had with aides to Gen. Boykin.

The general, a former commander of the elite Delta Force, is one of the Pentagon's most experienced special operations officers.

Boykin has participated in numerous special operations, from the Iran hostage crisis to Grenada, Somalia and the Persian Gulf War.

But Boykin also is controversial. He is best known outside the military as a fundamentalist Christian who on several occasions publicly has alluded to the United States' being in the midst of a religious war against Satan in the Middle East.

During one conversation Idema had with Jorge Shim, an aide to Boykin, Idema asks Shim for help. Defense lawyers claim the conversation occurred days before Idema was arrested.

Shim passes Idema to a man who says he's Shim's boss.

"We passed all your information to the J2 staff here and to the DIA [Defense Intelligence Agency]," the supervisor says. He then goes on to say: "And we were trying to protect our boss ... because he does not need any other scrutiny right now by the press. So we are trying to put a firewall between your efforts and him..."

Why should one of our nation's top commanders of covert operations need to create a "firewall" between himself and a bunch of bounty hunters in Afghanistan?

The judges at the kangaroo court in Kabul dared not go there. Just lock up the vigilante Americans, they said.

As for help from our government, don't count on it.

"The Afghan government held the trial in accordance with Afghan law," State Department spokesman Richard Boucher said.

Juan Gonzalez is a Daily News columnist.

###