Detective who gave shaky evidence at bail hearing is on seven charges himself over alleged drunken shoot-up

The prosecution case against the Olympic and Paralympic star Oscar Pistorius has been dealt serious blows after South African police admitted a series of blunders in their murder investigation – and the chief investigator turned out to be on attempted murder charges himself.

Hilton Botha, the detective leading the investigation, had crumbled under defence cross-examination on Wednesday after he wrongly claimed to have found boxes of "testosterone" in Pistorius's bedroom and admitted that police had no evidence contradicting the athlete's version of events.

On Thursday further pressure was piled on South African police as they admitted Botha is himself charged with attempted murder.

Police Brigadier Neville Malila told the Associated Press that the detective is scheduled to appear in court in May. Malila said Botha faced seven counts of attempted murder over what news reports called a drunken incident in which he and two other police officers were accused of firing shots from a state-owned vehicle while trying to stop a minivan.

Pistorius, a double leg amputee known as the Blade Runner, has admitted shooting dead his girlfriend, Reeva Steenkamp, 29, while she was in the bathroom of his home on 14 February, but claims he mistook her for an intruder. He denies a charge of premeditated murder.

Sitting in the dock at Pretoria magistrates court for his bail hearing, Pistorius looked more calm and composed than at any point so far, while the smiles on his family's faces suggested that they felt momentum was shifting his way.

The lead protagonist in another day of drama on Wednesday was chief investigating officer Botha, who initially asserted that he had found two boxes of "steroids" in Pistorius's bedroom, electrifying the courtroom. But he hastily corrected himself to say "two boxes of testosterone, needles and injections".

Later, questioned by advocate Barry Roux for the defence, Botha had to admit he could not be certain of the contents. Roux said it was a "herbal remedy" called testo-compositum co-enzyme used by many athletes, insisting: "It is not a steroid and it is not a banned substance."

The state prosecutor's office later said there was an error in the detective's testimony when he identified the substance as testosterone. Medupe Simasiku, a spokesman for South Africa's national prosecution agency, said it was too early to identify the substance as it is still undergoing laboratory tests.

Roux piled on the pressure on Botha after he told the court that one of his witnesses heard a fight – "two people talking loudly at each other" – between 2am and 3am on 14 February.

Questioned by Roux, he conceded the witness had not identified the voices as belonging to Pistorius and Steenkamp – and lived 600 metres away in a gated community. There was a collective murmur from Pistorius's family. Botha later changed his estimate to 300 metres when questioned by the prosecution.

Botha acknowledged that Pistorius's legal team had also found a spent bullet cartridge in the toilet bowl in the bathroom that his officers had not. He also confronted Botha, saying: "You were in the house walking with unprotected shoes. That should not happen." Botha conceded that it should not.

Botha said police found two iPhones in the bathroom and two BlackBerrys in the bedroom, adding that none had been used to phone for help after the shooting. But Roux claimed the defence team had another phone in its possession that the police had failed to request. "Why did you not come to us and ask for Pistorius's cellphone number?" he asked.

Roux also took him to task for failing to check Pistorius's claim that he phoned the Netcare hospital at 3.20am.

Botha said ammunition for a .38-calibre weapon had been found at the house but Pistorius did not hold a licence for it. "Did you take steps to find out who the owner of the ammunition was?" Roux asked. Botha replied: "No, I didn't." He also acknowledged that his investigators did not take photographs of the ammunition and allowed Pistorius's friends at the scene to take the cartridges away.

Wilting under pressure, Botha conceded that he had initially said there would be "no problem" with Pistorius receiving bail but changed his mind after talking to forensics about "how it went down".

Yet asked repeatedly by Roux if he found anything at the scene inconsistent with the account presented by Pistorius in court on Tuesday, Botha confessed that he had not. Nor did he have any evidence to suggest the couple were not in love. Police "take every piece of evidence and try to extract the most possibly negative connotation and present it to the court", Roux said.

The criticism continued at the end of his testimony, when magistrate Desmond Nair noted that Botha was opposed to Pistorius receiving bail on the grounds that he was a "flight risk". Nair said the accused was an international Paralympic athlete who uses prosthetic legs and whose face is internationally recognised.

"Do you subjectively believe he would take the opportunity, on prostheses as he is, known as he is, to flee South Africa if he was granted bail?" Nair asked.

Botha, who has 24 years' experience as a police officer and 16 as a detective, replied: "Yes."

That was met by an outburst of laughter in court, where the mood has mostly been tense and sombre.

The magistrate pressed: "And if he were to flee, he may opt for a country with no extradition agreement with South Africa?"

"It's possible, that's all I can say," the detective replied.

Pistorius, 26, had said in an affidavit read in court on Tuesday that he and his girlfriend had gone to bed on 13 February and that when he awoke in the early hours of the morning he detected what he thought was an intruder in the bathroom.

He testified that he grabbed his 9mm pistol and fired into the door of a toilet enclosed in the bathroom, only to discover later that Steenkamp was there, mortally wounded.

As on previous days, Pistorius looked vulnerable in the dock, struggling and sometimes failing to hold back tears. As the prosecution ran through its case against him, he sobbed.

The court was again congested with criminologists, journalists and legal officials. A sketch artist, Jaco Van Vuuren, could be seen drawing Pistorius's face.

The prosecution argued that the couple had a shouting match, that Steenkamp fled and locked herself into the toilet and that Pistorius fired four shots through the door, hitting her with three bullets.

"I believe that he knew that Reeva was in the bathroom and he shot four shots through the door," said Botha, adding that the angle at which the rounds were fired suggested they were aimed deliberately at somebody who was on the toilet.

One point of dispute is whether Pistorius was wearing his prosthetic legs when he shot through the bathroom door. In his statement on Tuesday, the athlete said he was on his stumps and feeling vulnerable when he opened fire.

But the prosecution has claimed the killing was premeditated because Pistorius took time to put on his prosthetic legs first. Botha supported this view, saying the trajectory of the bullets through the door showed the gun was fired from a height. "It seems to me it was fired down," he said.

Prosecutor Gerrie Nel projected a plan of the bedroom and bathroom on to a white screen in the court and argued Pistorius had to walk past his bed to get to the bathroom and could not have done so without realising Steenkamp was not in the bed. "There's no other way of getting there," Nel said.

Botha said the holster for the 9mm pistol was found under the side of the bed on which Steenkamp slept, also implying it would have been impossible for Pistorius to get the gun without realising that Steenkamp was not in the bed and could have been the person in the bathroom. Pistorius has claimed that the bedroom was pitch dark.

Botha cited another witness who claimed to have heard "two-to-three shots", seen Pistorius's lights on, then 17 minutes later heard another "two-to-three shots." He said: "We have the statement of a person who said after he heard gunshots, he went to his balcony and saw the light was on. Then he heard a female screaming, then more gunshots." Roux again contested the claim.

Botha said Steenkamp was shot in the head over her right ear and in her right elbow and hip, with both joints broken by the impacts. The shots were fired from 1.5 metres, he added, and police found three spent cartridges in the bathroom and one in the hallway connecting the bathroom to the bedroom.

Officers found the victim downstairs covered in towels and wearing white shorts and a black top. The detective said that all Pistorius would say after the shooting was "he thought it was a burglar".

Guards at the gated community where Pistorius lives did call the athlete, Botha said. The detective said that all the athlete said was: "I'm all right," before crying. "Was it part of his premeditated plan, not to switch off the phone and cry?" Roux asked sarcastically.

But the prosecution did land some blows on the athlete's character. Botha claimed that Pistorius was involved in another shooting at a restaurant in Johannesburg in January and, aware of the media storm that would ensure, asked the gun owner to "take the rap" for the incident, which he did.

Botha told the court of a further incident at a racetrack where Pistorius allegedly threatened to "fuck up" a man during a row over a woman.

As the day wore on, Pistorius's brother Carl moved to the front desks and sat beside the defence team. At one point he turned to Pistorius and smiled.

Carl said later: "I feel like the court proceedings went well today. We trust that everyone has more clarity about this tragic incident."

Kenny Oldwage, Pistorius's lawyer, added: "We're very pleased with today."

The hearing was adjourned to Thursday morning when a decision over bail might be made.