A BIKIE informant inside the NSW Police Force has leaked sensitive information about several criminal investigations, risking the safety of undercover police agents.

The infiltration of state and federal drug inquiries by the Comanchero bikie gang has been described as one of the worst cases of alleged corruption in the NSW Police in recent years.


Officials suspect the leaked information includes intelligence gathered by Australia's elite crime fighting body, the Australian Crime Commission, the NSW Crime Commission and the NSW Police.

Police officials suspect that the contents of more than a dozen NSW police files were obtained by the Comanchero, affecting up to eight criminal investigations.

The information obtained by the bikies jeopardised the safety of undercover police operatives because it triggered suspicion in the gang about spying within its own ranks.

It is understood that after the leak was detected about the middle of last year authorities took urgent steps to protect the welfare of an undercover police operative and to identify the leaker.

Late last year NSW Police anti-corruption investigators charged the suspected informant, the police analyst Terry Gregoriou, with stealing three police documents.

Mr Gregoriou has worked as an unsworn police analyst for several years, including in roles which gave him access to information on organised crime investigations.

A joint investigation by Fairfax and the ABC TV's Four Corners into organised crime, to be aired on Monday, reveals that the leaks occurred during one of Australia's most significant multi-agency criminal inquiries.

"In terms of the actual value of the information being leaked, I would rate it a five out of 10,'' said one senior policing source said. ''But in terms of its ability to possibly expose undercovers, it would be a nine out of 10."

Law enforcement sources said they suspected that associates of the Comanchero actively cultivated Mr Gregoriou to work for them while he simultaneously worked for the police.

After suspicion about Mr Gregoriou began growing last year, law enforcement officials fed into the NSW police database misinformation about his associates to see if he would access it, which he allegedly did.

The Comanchero operate in Sydney, Perth and Melbourne, and some of the group's members are variously involved in alleged organised crime activity, including drug trafficking, extortion and the nightclub industry.

A requirement in the law to show that a defendant has profited from their conduct - which police were unable to show in Mr Gregoriou's case - means he faces only the less serious summary offences of larceny and unlawfully disclosing information as a public official.

It is alleged he leaked information to his friend Peter Vassily, who in turn leaked it to associates of the Comanchero. Mr Vassily, 28, who faces charges of receiving stolen goods and possessing prohibited items, has long associations with figures connected to outlaw bikie groups.

Mr Vassily owns a real-estate business, Deakin Industrial Realty, in Arndell Park with Hakan Tukel, who, with his brothers Fidel and Baris, is linked to bikie gangs and organised crime figures. Baris Tukel is an associate of the Comanchero, and Fidel Tukel is an associate of the Rebels.

Several months ago Hakan Tukel posted a ''special message to [NSW police anti-bikie squad] Raptor'' which says ''grow up or man up … dropping lies and names is a no no … ".

Fidel and Hakan Tukel are well known in boxing circles, having a long involvement in Blacktown Hit Squad gym. Fidel Tukel promotes boxing events in Sydney and Melbourne.

It is not the first time state anti-corruption police have uncovered the infiltration by outlaw bikie gangs of law enforcement agencies. In late 2008 Victorian police files that potentially compromised state and federal drug trafficking investigations were leaked to the Black Uhlans.

Mr Gregoriou is suspended with pay from the NSW Police. He will appear in Downing Centre court on Monday.