Officials say top FBI agents unsuccessfully pushed to interview Timothy McVeigh all the way up to his execution.
Sources say the agents wanted to fill in unanswered questions about McVeigh's whereabouts leading up to 1995's Oklahoma City bombing.
The sources tell The Associated Press the plan to question McVeigh was scrapped when officials couldn't agree on who would attend and how it would be conducted.
Officials say they were also distracted by the belated discovery of thousands of pages of documents that hadn't been turned over to the defense. That late discovery prompted a one-month delay in McVeigh's execution.
Even during the delay, FBI and Treasury agents pushed for access to McVeigh on death row. Officials want to know if McVeigh may have had more co-conspirators than previously thought.