Despite commonly held beliefs, it's unclear whether the Columbine shooters timed that attack to mark either Adolf Hitler's birthday or the Waco incident.

CNN: Boston Marathon bombing: The latest Patriots Day tragedy

Mark Foxall from the authority said it was unclear if the damage was accidental or not.

BBC: Shrewsbury Cemetery graves extensively damaged

That's an improvement from the 13- to 14, 000 customers who were without electricity at one point, but it's unclear when power would be restored to everyone, spokesman Mark Davis said.

CNN: Tornado tears through southern Mississippi

But it remains unclear whether decapitating al Qaeda's infamous figurehead will mark a turning point in a war that has left thousands of Americans dead and killed untold numbers of civilians.

CNN: Americans take to the streets amid news of bin Laden's death

The result of what this mark-to-market process will look like this year is unclear.

FORBES: Magazine Article

As Mark Hudson, Kable's managing director, explains, it is unclear if everybody is counting the same costs, since the Home Office has not released detailed accounts.

ECONOMIST: Identity cards

It's unclear whether Los Angeles Superior Judge James Dabney knew Morningside was unlicensed when Lohan's lawyer Mark Heller informed him in court Thursday morning that she would spend her rehab sentence there.

CNN: SHARE THIS

It's unclear whether Los Angeles County Superior Court Judge James Dabney knew Morningside was unlicensed when Lohan's lawyer, Mark Heller, informed him in court Thursday morning that she would spend her rehab sentence there.

CNN: SHARE THIS