The father of a university student who died following an anti-government protest in Tseung Kwan O last year has urged anyone who saw what happened to his son to contact him, as an inquest gets underway into the death.

Chow Tsz-lok, 22, was found with massive head injuries in a car park on November 4 last year. He died in hospital after spending four days in a coma, during which time he underwent operations on his brain.

Speaking to the media on the first day of the inquest, Chow’s father urged people who witnessed the incident to contact him personally.

He said he just wanted to help his son a little bit more, "so he could rest in peace".

"I just hope [we] can find out the truth, or something closer to the truth," he said.

Chow's father told the Coroner's Court that his son, who was a computer science student at the University of Science and Technology, had left home late on November 3 wearing a black T-shirt and carrying a backpack.

He said he had told his son to be careful but got no reply, explaining to the court that he made his warning after seeing on the news that there were protesters and police at Sheung Tak Estate near their home.

The father said at around 12.45am on November 4 he messaged his son telling him that tear gas was being fired. Around two minutes later, his son replied, telling him to close the windows.

Chow Tsz-lok was last seen online at around 1am, his father said. An hour or so later friends of the student came knocking on the door to say he had been injured in a fall.

The father described his son as a quiet person and while he felt like the 22-year-old didn't always like talking to him, their relationship was not bad.

Speculation was rife at the time of the student's death that he had fallen from one floor of the car park to another, possibly while trying to escape police tear gas or while running away from riot officers.

A senior police inspector, who led a team of riot officers into the car park on the night in question, told the court that her team had not arrested anyone during their brief patrol there.

Yip Po-kei said she and her 10 or so colleagues entered the car park at around 11:10pm, but most of the protesters had left by the time they arrived. She said her team stopped and searched a man in the car park but let him go soon afterwards.

Yip added that they left the car park at 11:20pm and their operation ended shortly after midnight.

Two men and three women form the jury for the inquest which is expected to last 25 days, with 40 witnesses to be summoned in total.