Barrister-turned-informer Nicola Gobbo claimed she secretly edited the statements of a gangland hitman, casting doubt on more convictions.

If true, the act of doctoring statements also leaves Ms Gobbo and the detectives involved open to being charged with perverting the course of justice.

The hitman, who cannot be identified, gave more than a dozen statements about gangland figures to police after he was arrested in 2006.

He was the main witness against Faruk Orman, whose conviction for the murder of Victor Peirce was quashed last month because of Ms Gobbo’s involvement.

Ms Gobbo boasted to her police handlers in 2008 that she edited his statements after his arrest in mid-2006. Ms Gobbo, who represented the hitman, said she did so without his knowledge in the offices of gangland taskforce Purana, a royal commission has heard.