The investigating officer has challenged Oscar Pistorius' account because of the angle of several shots fired in the athlete's bathroom.
In an affidavit given on Tuesday, Pistorius said he woke in the night and thought an intruder had climbed through his bathroom window and entered the adjoining toilet.
He said he went into the bathroom without his prostheses and fired at the locked toilet door, believing the intruder to be inside.
But investigating officer Hilton Botha said the "top to bottom" trajectory of the bullets suggest Pistorius was wearing his prostheses.
He also said the angle of the shots suggests they were aimed at someone sitting on the toilet.