Government witnesses in a case against four alleged members of the Aryan Brotherhood prison gang have exaggerated their own importance and received perks including cash and reduced sentences for their cooperation, defense attorneys said.

A federal prison official, under questioning by defense attorneys Wednesday, testified that six inmates who were helping the government in its racketeering case against the gang were housed in a unit where they could mingle, use a computer and share information.

The government is trying to dismantle the Aryan Brotherhood's leadership using a federal racketeering law originally passed to target the Mafia. One of the largest capital murder cases in U.S. history, it alleges the defendants ordered or committed many of the 32 murders and attempted murders in an indictment.

The defense is seeking to show that prosecution witnesses have had the opportunity to manufacture incriminating stories about the defendants.

Danny Shoff, a Bureau of Prisons official now assigned to Washington, D.C., said he was one of the few staff members at the Supermax prison in Florence, Colo., allowed entry to "H Unit" at the time when the inmates were helping the government crack the heart of the Aryan Brotherhood.

Shoff said he was aware that "H Unit" inmates were using a computer and were producing documents, but was not sure whether they had access to internal prison databases that could have given them information that they would then represent as their own.

The trial follows the arrests of 40 people in 2002 after a six-year investigation. Nineteen of the defendants struck plea bargains, one died and trials of the remainder are pending.

The attorney for alleged ringleader Barry "The Baron" Mills, Mark Fleming, presented documents produced by inmate Danny Weeks, one of the key informants. He suggested that detailed notes Weeks made in tiny handwriting contained numbers taken from one or more prison databases.

"Can you think of any explanation of why Danny Weeks would have such information?" asked Fleming.

"No," Shoff replied.

Shoff also testified that Weeks initially claimed he was an Aryan Brotherhood dropout but later changed his story and said he was a mole sent in to "H Unit" to disrupt the government's investigation.

The defense opened its case Tuesday after weeks of prosecution testimony. A federal agent testified that many of the gang's former members were promised reduced sentences — and sometimes released — in exchange for their help. One inmate received $150,000 when he was released and placed into a witness-protection program, the witness said.

Mills is serving two life terms for the 1979 killing of a fellow inmate. In the current trial, he faces a possible death sentence for allegedly orchestrating the 1997 killings of two black inmates in Pennsylvania.