New questions are being raised about whether Timothy McVeigh and Terry Nichols really built and carried out the Oklahoma City bombing on their own, which is bad news for public trust in the official government account.

• Investigators close to the case never believed two men could have built the bomb by themselves.
• One defense theory holds McVeigh was recruited by others to be the fall guy and take all the blame.
• McVeigh confessed to the bombing, but sometimes slipped into "we" when describing the plan, hinting at accomplices.
• His confession may have been driven by wanting to be remembered as the mastermind rather than the mule who got caught.

Outlook: Expect more pressure on the FBI and Justice Department to release records about possible co-conspirators.