Updated

In a drama played out behind closed doors, senior FBI agents unsuccessfully sought permission in 2001 to interview Timothy McVeigh (search) to resolve lingering questions about the case before the convicted Oklahoma City bomber was put to death, officials say.

The agents wanted to clear up uncertainties about McVeigh's whereabouts on specific dates that were left unanswered by his public statements and the evidence, essentially filling in gaps in his timeline before the bombing, the officials told The Associated Press.

The plan was scrapped when the government couldn't resolve who would attend the interview or how it would be conducted. Officials also became distracted by the belated discovery of some 4,000 pages of documents that had not been turned over to McVeigh's defense during his trial.

That discovery prompted a one-month delay in McVeigh's execution, during which FBI and Treasury agents continued to press unsuccessfully for access to McVeigh on death row.

The interview debate was described by several current and former officials. They said it showed the government didn't know everything it wanted about McVeigh before he was put to death.

The officials said the potential interview became a primary focus of the remaining McVeigh investigative team during the spring of 2001 and was the subject of a high-level meeting in Oklahoma City (search) in March of that year.

The officials said the debate was documented in numerous FBI e-mails, and they were uncertain whether those e-mails should have been turned over to lawyers for the upcoming Oklahoma state murder trial of Terry Nichols (search), McVeigh's co-conspirator.

Besides filling in the gaps for McVeigh's whereabouts, one senior official said agents had seen instances in the past where "death row inmates were willing to give us some of their thought processes as their execution neared, and we hoped McVeigh might do the same."

The officials would only discuss the interview debate on condition their names not be used. The Justice Department has ordered its employees not to discuss the McVeigh case as Nichols' trial begins this week.

New information has been emerging nine years after McVeigh's massive fertilizer bomb killed more than 160 people at the Alfred P. Murrah building (search) in Oklahoma City on April 19, 1995.

Last week, AP reported that FBI agents in another case developed evidence suggesting a gang of white supremacist bank robbers might have become involved in McVeigh's conspiracy, but the agents failed to forward some of the information to their colleagues in the Oklahoma case.

That prompted the FBI on Friday to reopen portions of the case to determine whether other conspirators were involved, and the judge in the Nichols' trial warned he might dismiss the case if defense lawyers provided proof information was withheld from Nichols.

Several officials said the debate over interviewing McVeigh continued between the FBI, Justice Department and Bureau of Alcohol, Tobacco and Firearms without resolution, ending when McVeigh was executed in June 2001.

Some called it a missed opportunity, especially because much of the speculation about additional accomplices in the Oklahoma City case focused on periods in which there were uncertainties about McVeigh's whereabouts.

For instance, agents never were able to determine where he spent the final night before he detonated his bomb. They also wanted to inquire about time he spent in Arizona in February 1995, when he began to finalize his bomb design.

FBI agents determined McVeigh tried unsuccessfully to contact an explosives expert while in Arizona, and they wanted to know whether he sought help from anyone else.

An Oklahoma newspaper, the Idabel McCurtain Daily Gazette, and a college criminology professor, Mark Hamm, have studied McVeigh's movements extensively and developed timelines showing the white supremacist bank robbery gang was in the same vicinity as McVeigh several times during gaps in the government's official version of events.

"You have to use logic here. What is the probability of these things happening?" said Hamm, an Indiana State University professor who wrote a book identifying at least four intersections of McVeigh and the robbers between 1993 and 1995.

"If it was one time, you might chalk it up to coincidence. If it is two times, you might begin to ask some serious questions. But when it gets to three and four times, that suggests there clearly is an ongoing conspiracy," he said.

For instance, the bank robbers were in Arizona during some of the same time as McVeigh in February 1995. Just a month earlier, in a videotape the robbers made they display an explosives manual while bragging about plans to kill government officials.

Hamm said he placed McVeigh and the bank robbers together in December 1994 at a gun show in Overland Park, Kan., and again in 1993 when they were in a rural Arkansas town on the same day.

Another parallel occurred in November 1994: McVeigh was in Ohio, near a bank the gang would rob a month later, on the day that an Arkansas gun dealer was robbed to provide the proceeds for McVeigh's bombing.