The city's top court yesterday dismissed an appeal by two police officers jailed after being recorded fabricating evidence against an alleged brothel operator.
Sergeant Yeung Ka-ho, 35, and constable Chow Chi-pang, 37, had taken their case to the Court of Final Appeal, arguing that the recordings should not have been used as evidence to convict them as it was unsafe to identify people by their voices.
In the judgment, Mr Justice Thomas Gault wrote: "I see no reason why, in certain circumstances, the identity of participants, and the timing and circumstances of a recorded conversation, cannot be proved by reference to the content of the recording."
The judge said the identification of the speakers "must be possible" even though the recording's makers were unknown and unavailable.
"The content, when placed in a context of known facts, establishes time and place," he said.
The tapes led to the acquittal of nine people accused of running saunas to provide sexual services. The two policemen were jailed for two years and three months in 2011 for perverting public justice and misconduct in public office.