Some details:

Witnesses told The Star that excessive pressure often came from Dave True, now a retired agent for the Bureau of Alcohol, Tobacco, Firearms and Explosives, which helped investigate the case.

Two witnesses said that True enticed them with reward money for their testimony at a time they were vulnerable or addicted to drugs. Some said True told them he would do whatever it took to solve the case before he retired.

There's no doubt about this:

“We routinely threaten people with their loss of freedom” if they’re in trouble with the law and refuse to cooperate in solving crimes, [Asst. U.S. Attorney Paul] Becker said.

Unfortunately, witness often interpret "cooperate in solving crimes" not as "tell us what you know" but as "tell us what we want to hear or else we'll lock you up." Faced with that choice, the pressured witness will often provide whatever "facts" the government seems to be looking for, regardless of their truth. It's even worse (and in fact crosses the fine line from "routine" to "illegal") when the feds actively try to suborn perjury.

The possibility that at least some of the five defendants are innocent is substantial:

An ongoing investigation by The Kansas City Star raises serious questions about the federal trial that convicted Brown and the others.

•All the defendants had alibis, and the three given polygraph tests passed.

•Witnesses have since recanted.

•Evidence helpful to the defendants was never used by defense attorneys.

Links to all of the Star's recent coverage are here.