Security camera footage captured a flash on the top of a seven-seater inside a Tseung Kwan O car park at around 1am, which police said was caused by the light reflecting off University of Science and Technology student Chow Tsz-lok during his fall, the Coroner's Court heard.

Chow, then 22, died from brain injury four days after he fell from the third to the second floor at Sheung Tak Estate car park in the early hours of November 4 last year, while police clashed with protesters nearby.

Ngai Kwun-kit, a detective police constable at the Kowloon East regional headquarters, yesterday testified before coroner Ko Wai-hung on the 12th day of the inquest into Chow's death.

Ngai said he collected CCTV footage from 35 cameras inside the car park from its managing staff on November 5 last year and watched all of them to trace Chow's whereabouts.

Some of the footage was played in court. Chow, dressed in a black shirt and shorts, entered a pedestrian bridge connected to the car park at 12.26am.

He appeared on the second floor at 12.28am and was seen wandering around afterward.

Chow was last seen at 1.01.39 am when he was walking to the third floor. Eight seconds later, a flash appeared on top of a seven-seater parked on the second floor.

The light was reflected off Chow's falling body and captured by the camera, according to Ngai.

He said Chow was alone and was not being followed in all the footage, adding Chow was either checking his phone or looking around the whole time.

Ngai denied that the footage had been edited by him or anyone else.

He said while he asked for all the CCTV footage during the incident, the manager did not give him those filmed in the car park's elevators.

Coroner Ko said it is still too early to confirm whether the flash indicated the exact timing of Chow's fall.

The matter will be discussed further when the court summons experts from the police's identification bureau to testify, Ko added.

He said that there is enough evidence to show Chow's fall happened in the five minutes from 1.01.39am, when his body was discovered by a citizen on the second floor.

The hearing continues today.

mandy.zheng@singtaonewscorp.com

Flash sheds light on death of student