Security footage led detectives to single out one of 40 immigration officers as a suspect in the theft of three laptop computers containing sensitive data from the airport's immigration office last month, police say.
But they fear the suspect could escape prosecution if the Immigration Department computers are not retrieved and no new evidence is found.
The interior of the locked immigration office where the laptops were kept is not covered by surveillance cameras. It is understood the computers stored the personal data, including passport images, of about 3,000 transit travellers who immigration officers had deemed to be suspicious in some way upon arrival. Their travel documents had been scanned to prevent such visitors from using other identities to board other flights or to revisit the city.
The data was transferred to the department's server and deleted regularly if no further suspicions arose.
A police source said a closed-circuit television system at the airport's restricted area captured the suspect walking out of the office with a bag that appeared to contain heavy objects.
The suspect was among a handful of immigration officers who were observed entering and leaving the office during the period when the devices were stolen.
"We have identified this suspect, but we need evidence to present in court," the source said. "The missing computers are crucial evidence in the case."
He admitted that the suspect might go unpunished if the laptops could not be recovered.
"The suspect is also in law enforcement and knows this well," the source said. There was no indication that the data was the intended target of the theft, the source said. "We believe the immigration officer simply found an opportunity to steal the laptops," the source said.
It is believed the computers were taken away from the airport and probably sold to a second-hand goods trader for a few thousand dollars.
As part of their search, New Territories South regional crime unit officers interviewed traders and hawkers in the Apliu Street second-hand electronic goods market in Sham Shui Po, but to no avail. They also made a fruitless search of the homes of some of 40 immigration officers who were under investigation.