There was no plan, the former Kings Cross detective claims, to murder 20-year-old drug dealer Jamie Gao in a south-west Sydney storage unit and then dump his body in the ocean off Cronulla Beach.

His barrister told Central Local Court that things suddenly went wrong when Rogerson's former police colleague Glen McNamara and Mr Gao were inside the Padstow shed – and the 73-year-old agreed to help clean up the mess.

"If that is the case then he's not even guilty of accessory after the fact to murder," Rogerson's barrister George Thomas told the court on Monday.

In opposing his application for bail, Crown prosecutor Christopher Maxwell, QC, revealed prison officers had recorded a phone conversation between Mr Rogerson and his wife.

"I kept looking at the f---ing [CCTV] camera and thinking: 'Why would you go there [to commit a crime]?" Rogerson allegedly told his wife of the moment when Mr McNamara and Mr Gao entered the storage unit, which was recorded on CCTV.

"It's the last place in the bloody world," he allegedly continued. "He [Mr McNamara] just wanted to go somewhere quiet."

When Mr Rogerson's wife asked him why he had then joined the two men in the unit, he said: "They had been there for a while and I just wanted to see what was happening. I just wanted to give him [Mr McNamara] some fatherly advice."

But Mr Thomas provided what he described as an "alternative, rational, reasonable hypothesis" to explain CCTV footage showing Mr Rogerson and Mr McNamara going to the storage shed on their own, returning later with Mr Gao, and then removing his body from the unit in a silver surfboard bag.

The barrister said Mr Rogerson had gone to the storage shed because his old colleague Mr McNamara had been concerned that he was being followed by Mr Gao's associates, whom he believed were members of an Asian triad.

Mr Rogerson had also allegedly been interested in speaking with Mr Gao because he was "seeking to engage in the publication of further material" – a reference, the court heard, to the former detective's writing about his experience of Sydney's criminal underbelly.

"Mr Gao was a person my client had never met, let alone knew," Mr Thomas said as Mr Rogerson, appearing via video link from Silverwater prison, took notes.

"He was there simply to take part in a meeting."

During the animated but ultimately unsuccessful bail application, Mr Rogerson's defence to the charge of murder over Mr Gao's death on May 20 was revealed.

Mr Thomas told the court that the three or four minutes Mr McNamara and Mr Gao spent in the storage shed before his client entered was more than enough time for the killing to have taken place.

He said that when Mr Rogerson did enter the unit, Mr McNamara told him Mr Gao had come at him with the weapon and in the ensuing struggle, had been shot with his own weapon.

Mr Thomas suggested that Mr Gao himself might have brought the gun into the storage shed.

"The Crown speculates that what was in the package [Mr McNamara was carrying] was the firearm, but what was the evidence to support this proposition? Zero, zippo, nothing!"

He said the police had been unable to answer some basic questions in the case.

"Do you know who fired the fatal shots? No we don't. Do you know if the shot was fired by Roger Rogerson or someone else? No we don't. Do you know if there was a struggle? No we don't. Do you know whether Mr Gao produced the firearm, raising a possible self-defence argument? No, we don't know anything about that."

Mr Maxwell told the court Mr Rogerson had "control and access to the scene of the killing" in the form of the code and keys to the storage shed, which he had visited the day before.

But Mr Thomas said this had been obtained from a friend of Mr Rogerson's back in April so that the former officer could help him move a number of chairs around.

He described the Crown's case as "weak" and its arguments against bail as based on a "significant degree of false construction and speculation".

But Mr Maxwell said that even if Mr Rogerson was not in the unit when the fatal shot was fired, he was "part of a joint criminal enterprise".

In the end, magistrate Les Mabbutt rejected Mr Rogerson's offer of a $1.5 million bail surety and his claim that a series of medical conditions demanded he be on liberty until his trial.

He said there was an unacceptable risk that Mr Rogerson would either flee or commit another offence.