But prosecutors and Pistorius' defense battled over allegations that testosterone and needles were found at the home, as well as the quality of the police investigation.
Amid speculation by outsiders to the case that steroids or other drugs could have somehow played a role in the shooting, Botha testified that investigators found two boxes of testosterone and needles at Pistorius' home.
Under questioning by Roux, however, Botha said he hadn't read the full name of the substance -- which Roux said was an herbal remedy called testoconpasupium coenzyme -- when investigators took the materials into evidence. A quick Internet search on the name of the substance yielded no results.
He also said the defense forensics team found a bullet in the toilet that police had missed and noted police had failed to find out who owned ammunition found at the home or photograph it.
Investigators also went into Pistorius' home without wearing protective foot covers to prevent contamination of the crime scene, Roux said. Botha conceded that was true and said it was because police didn't have any more of the covers left.
Roux questioned police arguments that a witness heard sounds of an argument before the shooting. The witness, Roux said, lives 600 meters (more than a third of a mile) from Pistorius' home. Prosecutor Gerrie Nel countered that the witness lives 300 meters away.
Would he run?
Botha told Magistrate Desmond Nair that investigators believe Pistorius is violent and might flee if released from jail.
He described two encounters with Pistorius, one in which Botha said the track star asked someone else to take the blame when a gun went off at a Johannesburg restaurant.
Police said the second incident took place at a racetrack, where Pistorius allegedly threatened to assault someone.
Authorities have also said they have responded to previous domestic incidents at Pistorius' home, but have not elaborated.
In his statement Tuesday, Pistorius said he and Steenkamp were deeply in love and said he was "mortified" over her death.
Defense attorneys are trying to overcome South African law, which makes it difficult for defendants accused of premeditated murder to get out on bail. The law requires evidence of "exceptional circumstances" to justify release.
Nair upgraded the charge against Pistorius to premeditated murder Tuesday, saying he could not rule out the possibility that the track star planned Steenkamp's death. But Nair said he would consider downgrading the charge later.
In a statement read by his lawyer Tuesday, Pistorius said he would not try to flee or influence any witnesses if he is allowed out on bail, and he said his release wouldn't be a danger to public order.
Case rivets fans and friends alike
The case of the global sports hero known as the "Blade Runner" has riveted stunned fans around the world.
Social media reaction to the case appeared to come down against the sports star but was still noticeably mixed on CNN's Facebook page.