A man who lives next to the house where Oscar Pistorius fatally shot his girlfriend has testified at the athlete's murder trial about the night of the killing, saying he heard a man crying loudly and that he called the security of the housing estate for help.

Michael Nhlengethwa testified Tuesday on behalf of the Olympian's defence team, which contends that Pistorius killed Reeva Steenkamp by mistake after believing there was an intruder in his home on Feb. 14, 2013.

The prosecution says Pistorius intentionally killed Steenkamp after the couple had an argument.

The disabled runner shot four times through a toilet cubicle door with his 9 mm pistol, hitting Steenkamp in the hip, arm and head.