Former cop charged over student's murder

A former police officer has been charged with murder over the alleged kiling of student Jamie Gao.

Ex-detective Glen McNamara, 55, was charged by police early on Monday morning.

Police were also searching for notorious former cop Roger Rogerson in connection to the alleged murder.

Rogerson is believed to be in Queensland.

A Sydney student feared abducted and murdered may have got himself "in over his head", detectives say.

Gao, 20, from Hurstville allegedly disappeared about 1.40pm last Tuesday after meeting two young men and getting into a white car on Arab Road, Padstow, in the city's south.

Police say he was excited about the "secret meeting" with the men in the days leading up to his disappearance.

"It's possible Mr Gao was getting himself into some kind of trouble and indeed may have been getting himself in over his head," Detective Superintendent Luke Moore told reporters in Sydney on Sunday.

"We don't know exactly who he was meeting or the exact purpose of the meeting.

"But the nature of why he was going there - and in fact it was quite secretive - leads us to believe he may have been getting himself into some kind of trouble."