The expert, Digbijoy Chakraborty, said that although a person could be located through his mobile phone even when it is not connected to the internet, the accuracy of the data would depend highly on the strength of the GPS signal at the location.

“You will not be able to determine the person’s location if the signal is blocked by walls, like if the person is in a room with concrete walls, or if the signal is simply poor,” he told FMT.

The question arose from a Suhakam inquiry into the disappearance of Perlis Hope activist Amri Che Mat.

Last Monday, Suhakam commissioner Mah Weng Kwai asked police to gather location data to verify a claim by Amri’s wife, Norhayati Ariffin, that she and Sergeant Shamzaini Mohd Daud had a meeting at her house during which the sergeant told her police were involved in her husband’s disappearance.

Norhayati spoke of the meeting during a hearing last May. Shamzaini subsequently lodged a police report disputing her claim.

Last Tuesday, police observers at the inquiry brought into question the accuracy of GPS location data, with ACP R Munusamy saying the data would be accurate only for up to two to three kilometres. The family’s lawyers, however, insisted on the accuracy of such data.

Norhayati told FMT yesterday she was not certain of the quality of the GPS signal at her house.

“But when I use certain applications, there is a GPS signal,” she said. “I just can’t tell for sure whether it’s a good or bad signal.”

Norhayati uses a Celcom phone number and lives in Perlis.