WBRZ - Baton Rouge

PRETORIA, South Africa - Oscar Pistorius says he shot his girlfriend to death by mistake, thinking she was a robber.

The double amputee said in an affidavit read by his lawyer at his bail hearing Tuesday that he felt vulnerable because he did not have on his prosthetic legs when he pumped bullets into the locked bathroom door.

Then he realized that model Reeva Steenkamp was not in his bed. He says "It filled me with horror and fear ..."

He put on his legs, tried to kick down the door, then bashed it in with a cricket bat to find Steenkamp, 29, shot inside.

He said he ran downstairs with her, but "She died in my arms."

Today, a South African prosecutor charged Pistorius with premeditated murder in Steenkamp's death.