New detective assigned to Pistorius case

South African police assigned a top new detective Thursday to take over the bungled Oscar Pistorius investigation after it emerged the lead officer faced seven charges of attempted murder, dramatically undermining the prosecution against the sprint star.

"We recognise the significance, the importance and the severity of the matter," police commissioner Riah Phiyega said as she announced the new appointment. "This matter will receive attention at the national level."

The charges against detective Hilton Botha further embarrassed the prosecution which has seen its evidence repeatedly picked apart during the bail hearing for Pistorius over the Valentine's Day killing of his girlfriend Reeva Steenkamp.

Pistorius himself suffered a new blow on Thursday when US sportswear giant Nike said it has suspended its contract with the double amputee Olympian and Paralympian known as "Blade Runner" who had become an inspiration to millions.

The 26-year-old is due back in court on Friday for the fourth day of the bail hearing.

Many think he will be let free pending the trial because prosecutors failed to prove Steenkamp's killing was premeditated -- a more severe charge which makes bail hard to get.

Police revealed Thursday that Botha is facing seven charges for shooting at a minibus taxi in 2011, and he also came under repeated fire from Pistorius' defence team over witness testimony and his handling of the investigation.

"The poor quality of the evidence of investigating officer Botha further exposed... the disastrous shortcomings in the state's case," said defence lawyer Barry Roux.

Pistorius says he mistook his 29-year-old model girlfriend for an intruder.

Steenkamp was found by medics in the early hours of last Thursday at Pistorius's luxury Pretoria home covered in bloodied towels, with bullet wounds to her head, elbow and hip. She died at the scene.

The athlete has previously said he kept a gun in his bedroom because of fears of violent burglary.

The sprinter, who has been in police custody for a week, could face months or perhaps years in pre-trial detention if he does not win bail.

The star athlete also shouldn't get preferential treatment, said Prosecutor Gerrie Nel.

"'I am Oscar Pistorius. I am a world renowned athlete. Can I get bail.' No, we have to look at the person," Nel said.

In a statement read out in court earlier this week Pistorius said that he had fired at the door of the bathroom where his lover was hiding as he was "filled with horrible fear" that someone had sneaked in through an open window in the dead of night.

Nel emphasised Pistorius still faces charges if he didn't intend to kill Steenkamp.

Under South African law shooting someone without immediate threat is punishable, and Pistorius fired while there was a chance for escape through his bedroom.

-- 'It could have been handled better' --

But Botha was forced to admit that Pistorius's claims were "consistent" with the crime scene and on Thursday he said of the investigation: "I'm sure it could have been handled better."

He has conceded he did not wear protective clothing when the forensic team visited Pistorius's home, which may have contaminated the scene.

He was further forced to admit that police had not seen a bullet that hit the toilet basin and which was only discovered four days later by the defence forensic team.

Roux on Wednesday also threw doubt on key prosecution witness evidence suggesting the couple, who had been dating since late last year, had an argument before the shooting.

A woman who lives in the same high security complex "heard talking that sounded like non-stop fighting from two to three in the morning," hours before she was killed, prosecutor Nel said.

Another witness "heard a female screaming two-three times, then more gunshots," Botha said.

But Roux disputed the accounts, as police said one witness was at least 300 metres (nearly 1,000 feet) from the house and the other had misheard the number of gunshots.

Prosecutors also backtracked on allegations that a police search had found testosterone and needles in a dresser in Pistorius's bedroom.

Pistorius's family said in a statement it was "satisfied" with the bail hearing, but "finds the contradictions in Botha's testimony extremely concerning".

Arguing that Pistorius would be a flight risk, the prosecution quoted a magazine article in which the runner claimed to have a house in Italy.

But his coach Ampie Louw told AFP the property is actually a training facility built by the local government and a hotel, where the athlete goes regularly to train and unwind.

Pistorius's career has been put on hold since the shooting, forcing him to cancel a number of races.

Nike on Thursday became the latest in a series of corporate giants to halt endorsements which have earned the athlete millions of dollars. US sunglasses maker Oakley has already suspended its contract with him and French cosmetics firm Clarins said it was dropping an advertising campaign featuring Pistorius.

The athlete became the first double amputee to compete at an Olympics at the London games last year.

Off the track he has had a rocky private life with stories of rash behaviour, beautiful women, guns and fast cars. He has built up a powerful team of lawyers, medical specialists and public relations experts for his defence.