The first witness in the Oscar Pistorius murder trial testified Monday to hearing a woman's ''blood-curdling'' screams before the sound of four gunshots on the night the double-amputee Olympian killed his girlfriend. Michell Burger, a woman who lives on an estate next to Pistorius' gated community, said she and her husband were awoken by the screams in the pre-dawn hours of Feb. 14 last year, when Pistorius killed Reeva Steenkamp by shooting four times through a door in his bathroom. Pistorius says he killed Steenkamp by mistake thinking she was a dangerous intruder in his house, but prosecutors believe the world-famous athlete shot his girlfriend after a fight and immediately tried to paint a picture at the trial of a loud argument before the fatal shots. Burger's testimony contradicts Pistorius' version of events, because he said he thought Steenkamp was in bed and he did not describe any woman screaming.