Pistorius Says He Thought Girlfriend Was a Robber

South African Olympian and double amputee Oscar Pistorius has been formally charged with the premeditated murder of his girlfriend.

But Pistorius says it was all a mistake.

Pistorius said in an affidavit he shot through the bathroom door because he thought a robber was present.  He said he felt vulnerable because he was without his prosthetic legs.  Once he realized his girlfriend, Reeva Steenkamp,  was not in bed with him, he broke down the bathroom door and said she died in his arms.

But prosecutors say Pistorius took the time to put on his prosthetic legs and walk about twenty feet to the bathroom door where he opened fire.