The South African detective leading the Oscar Pistorius inquiry is facing seven charges of attempted murder, police have confirmed.
Detective Hilton Botha, who has faced fierce questioning at Mr Pistorius's bail hearing, was allegedly involved in a shooting two years ago.
Mr Pistorius, a Paralympic champion, denies the premeditated murder of his girlfriend Reeva Steenkamp, 29.
His bail hearing is now under way for a third day in Pretoria.
The defence argued again that the premeditated murder charge should be altered.
Separately, sports giant Nike has confirmed it has suspended its contract with Oscar Pistorius.
Police spokesman Neville Malila said that Det Botha and two other officers were due to appear in court in May.
Mr Malila said it was alleged that while driving a state-owned vehicle the three had opened fire on a minibus taxi loaded with passengers.
The three were arrested in 2011, Eyewitness News says, citing police.
Mr Malila said the charges against Det Botha had originally been dropped but were reinstated.
It is unclear when this took place or whether Det Botha will continue working on the case in the long run.
Medupe Simasiku, a spokesman for the Pistorius prosecutors, told Associated Press they were unaware of the charges and would now investigate whether the detective should remain.
The BBC's Peter Biles in Pretoria says the police statement concerning Det Botha is an extraordinary turn of events.
Mr Pistorius says he shot Ms Steenkamp in the bathroom of his home after mistaking her for an intruder.
If denied bail, Mr Pistorius could face months in prison before a full trial begins.
Thursday's proceedings began with prosecutor Gerrie Nel confirming to the court that Det Botha was facing seven attempted murder charges.
Det Botha was not initially in court and Magistrate Desmond Nair had to ask for him to be found.
After a short break, Det Botha was brought in and was questioned about telephone records from the night of the shooting, evidence of violence in Mr Pistorius's past and the extent of the flight risk.
Lead defence counsel Barry Roux then addressed the court and called for the charge to be listed as "schedule 5", not the current "schedule 6", which is one of premeditated murder.
The defence team would have to prove extenuating circumstances to justify granting bail if schedule 6 remains.
Mr Roux said: "The poor quality of the evidence offered by investigative officer Botha exposed the disastrous shortcomings of the state's case."
He said the fact that Mr Pistorius had carried Ms Steenkamp downstairs showed he was desperate to save her life.
Mr Roux also referred to witnesses the prosecution said had heard rows between Mr Pistorius and Ms Steenkamp that evening, saying they were too far away and that the state argument was misleading and desperate.
After the defence arguments, the prosecution will present its case.
Mr Roux told the BBC's Andrew Harding, who is in the courtroom, that a bail decision might not come until Friday.
Correspondents say Det Botha's evidence on Wednesday appeared first to boost the prosecution's case and then offer the defence a hope of winning the argument.
Det Botha told the court that the trajectory of gunshots through the bathroom door indicated that Mr Pistorius, a double amputee, was wearing his prosthetic legs and shot downwards through the door.
This contradicted an earlier account given by Mr Pistorius, who said he was walking on his stumps and grabbed his gun because he felt vulnerable when he thought an intruder had entered.
But Det Botha also amended his testimony on the proximity of the witness who he said had heard arguments.
Det Botha said police had lost track of ammunition found inside the house and was also accused of not wearing protective clothing at the crime scene.
The defence also countered police suggestions that testosterone and needles had been found in Mr Pistorius's bedroom, arguing instead that the substance was a herbal remedy, called Testocompasutium co-enzyme.
The magistrate appeared to question Det Botha's assertion that Mr Pistorius could be a flight risk who should be denied bail.
The Pistorius family issued a statement saying they were "satisfied with the outcome" of Wednesday's proceedings.
Oscar Pistorius won gold medals at the 2004 Paralympic Games in Athens, in Beijing in 2008 and London in 2012.
In London he made history by becoming the first double-amputee to run in the Olympics, making the semi-final of the 400m.