Police are in Queensland to talk with disgraced ex-detective Roger Rogerson over the alleged murder of Sydney 20-year-old Jamie Gao.

Former Kings Cross policeman turned anti-corruption whistleblower Glen McNamara is accused of murdering a student during a botched drug deal.

And Sydney police have flown to Queensland to try to track down disgraced former detective Roger Rogerson as part of its investigation into 20-year-old Jamie Gao’s disappearance and murder.

The 55-year-old McNamara appeared in Kogarah Local Court on Monday accused of murder and large commercial drug supply.

Police allege McNamara, who once gave evidence to a royal commission on police corruption, met with Mr Gao last Tuesday in southwest Sydney. The university student was reported missing the next day.

Investigators believe Mr Gao and two males went to the meeting place in Padstow with three kilograms of methamphetamine.

Detective Superintendent Luke Moore said Mr Gao was last seen getting into a white car, which drove off with a silver car following.

Police raided the Padstow Heights home of the notorious former Sydney detective Rogerson on Sunday.

After a silver car was taken from the home, investigators flew to Brisbane on Monday to try to find him.

Investigators won’t know until at least Tuesday whether a body wrapped in a blue tarpaulin found floating in the ocean off Cronulla on Monday is Mr Gao.

A fisherman made the grisly discovery.

Det Supt Moore said police believe Mr Gao was murdered near the Padstow meeting spot.

“The purpose of the meeting we now strongly believe, and we will be putting to the court, was for a drug transaction – a substantial quantity of prohibited drug,” he said.

On Sunday night, hours after police made an urgent plea for information about Mr Gao’s whereabouts, McNamara was pulled over in Sydney’s south.

He was charged with Mr Gao’s murder and is also accused of supplying 3kg of methamphetamine, also known as ice.

Police believe it was the same drugs Mr Gao took to the Padstow meeting.

After McNamara’s arrest, police raided his Cronulla home and seized a blue car and other items of interest.

A boat was also seized from a storage shed in Caringbah.

McNamara, who left the police force after a stint at Kings Cross station in the `90s, wrote two books on police corruption.

His family wept in the public gallery at Kogarah as the 55-year-old was led away on Monday.

McNamara has been put into protective custody and will appear in Central Local Court on July 22.

Meanwhile, Rogerson’s wife told Fairfax Radio her husband was in Queensland for a speaking engagement and was due to fly back to Sydney on Tuesday.

Rogerson is one of the most infamous policemen in NSW history.

The highly-decorated detective was dismissed from the force in the 1980s with his career later depicted in the ABC drama series Blue Murder.