Reacting to an AP story earlier this week, the FBI ordered agents to determine why some documents did not properly reach the bureau's Oklahoma City task force during the original investigation or get turned over to McVeigh's lawyers before he was executed in 2001, officials said.
The review of evidence and documents will also try to determine whether FBI agents in a separate investigation of white supremacist bank robbers may have failed to alert the Oklahoma City investigation of a possible link between the robbers and McVeigh, and allowed some of that evidence to be destroyed.
AP reported Wednesday that documents never introduced at McVeigh's trial showed FBI agents destroyed evidence and failed to share other information that raised the possibility that a gang of white supremacist bank robbers may have assisted McVeigh.
The evidence includes documents showing the Aryan Republican Army bank robbers possessed explosive blasting caps similar to those McVeigh stole and a driver's license with the name of a central player who was robbed in the Oklahoma City plot.
The documents don't prove additional accomplices were involved blasting caps are plentiful and the gang was expert in document fraud. But the FBI agent who ran the investigation, Dan Defenbaugh, said his team never got the chance to investigate the evidence and he called for the probe to be reopened.
The April 19, 1995, bombing killed more than 160 people and McVeigh was put to death for it in 2001. His co-defendant, Terry Nichols, will stand trial in Oklahoma next week on state charges that could carry the death penalty.
Nichols' attorneys asked Thursday for the trial to be delayed in light of the AP story, but the judge refused.
FBI officials and Nichols' attorneys declined comment Friday night, citing a gag order in the case.
Government officials, who spoke only on condition of anonymity, said the review will be handled by the FBI's inspection division, a unit of senior agents that routinely conducts reviews to ensure the bureau follows its own rules and conducts investigations properly.
The officials said the review was ordered ``out of an abundance of caution'' to ensure that any questions about additional conspirators be put to rest.
It is not the first time issues in the McVeigh case have had to be reopened. In 2001, the Justice Department was forced to conduct an internal investigation to determine why 4,000 pages of documents from the case were belatedly turned over to defense lawyers just days before McVeigh was supposed to be executed. The revelation prompted a one-month delay in the investigation.
Peter Langan, one member of the ARA robbery gang, told AP he plans to testify at Nichols' trial that federal prosecutors several years ago offered and then withdrew a plea deal for information he had about the Oklahoma City bombing.
Langan said he plans to testify that at least three fellow gang members were in Oklahoma around the time of the bombing and one later told him that they had become involved.
Agents who worked both the McVeigh bombing and the bank robbery spree two of the FBI's highest priority cases of the 1990s said they suspected a link between the two because of physical evidence as well as statements made by the robbers and a girlfriend.
The agents said they ruled out a connection when the bank robbers denied their involvement and provided an alibi showing they left Oklahoma three days before McVeigh's bomb detonated outside the Alfred P. Murrah federal building on April 19, 1995.
That alibi, however, was contradicted by information Langan offered prosecutors and by car sales records that showed the bank robbers were still in the Oklahoma area after they claimed to have left, FBI documents show.
McVeigh in 1994 stole from a quarry hundreds of construction blasting caps, some which he used to explode the Oklahoma City bomb. The FBI spent months unsuccessfully trying to locate many of the other stolen caps.
Agents collected witness testimony that McVeigh had placed some of the extra caps in two boxes wrapped in Christmas paper in the back of his car along with mercury switches and duffel bags.
One electric and five non-electric blasting caps were found in the Aryan Republican Army robbers' Ohio hideout in January 1996, along with mercury switches, a duffel bag and two items described as a ``Christmas package,'' FBI records show. The FBI allowed firefighters to destroy the caps at the scene, and they were never compared to the Oklahoma case.
FBI agents in the robbery case also determined that the bank robbers had an Arkansas driver's license in the name of Robert Miller, the alias name used by Arkansas gun dealer Roger Moore.
The government contended at McVeigh's trial that Moore was robbed at his Hot Springs, Ark., home in November 1994, and the proceeds were used to fund the Oklahoma City bombing.
One of the bank robbers, Mark Thomas, claimed in a newspaper in 1997 that one of his gang was involved in the Oklahoma bombing. And Thomas' ex-girlfriend told FBI agents her boyfriend stated shortly before he traveled to an Oklahoma white supremacist compound in spring 1995 that a federal building was about to be bombed.