Roux saved what was arguably the most significant witness after Pistorius himself, Tom "Wollie" Wolmarans, for the afternoon session.
Wolmarans, an extremely experienced forensics and ballistics expert, gave the court a detailed account of how a firearm works, how the South African Police Service's reassembly of the broken bathroom door and repeated probes through the bullet holes could have possibly caused variations in the test results, and said it would not be possible to accurately determine the sequence of shots.
He added that it was likely that Steenkamp was leaning slightly forward when she was wounded in the hip.
Wolmarans will continue his testimony Friday.
ABC News' Matt Gutman and The Associated Press contributed to this report.