Mr Roux's arguments drew to a cose as he complainedto the North Gauteng High Court that a number of witnesses refused to testify.
The athlete is charged with the "willful and intentional murder" of Reeva Steenkamp after he shot his then girlfriend dead at his home on February 14, 2013.
Pistorius has always maintained his innocence, insisting that he mistook Ms Steenkamp for an intruder after hearing a noise in the bathroom.
"We were unable to call a number of witnesses because they refused, and didn't want their voices heard all over the world," Mr Roux told the court on Tuesday.
There was nothing the defence could do to change their minds, he said, without elaborating on who the witnesses were.
The defence then closed its case.
The prosecution agreed to file its closing argument with the court on July 30, and the defence on August 4. The arguments will then be heard in court on August 7 and 8.
Judge Thokozile Masipa ordered that the contents of the arguments could not be published by print or broadcast media until they were heard in court.