PRETORIA, South Africa — Oscar Pistorius told a packed courtroom Tuesday that he shot his girlfriend to death by mistake, thinking she was a robber. The prosecutor called it premeditated murder.

The double amputee said in an affidavit read by his lawyer at his bail hearing that he felt vulnerable because he did not have on his prosthetic legs when he pumped bullets into the locked bathroom door. Then, Pistorius said in the sworn statement, he realized that model Reeva Steenkamp was not in his bed.

"It filled me with horror and fear ," he said.