An inquest has begun in Hong Kong into the deaths of eight tourists from the city, who died in a bus hostage drama in the Philippines last August.
A disgruntled armed former policeman hijacked their tour bus.
But the inquest will face difficulties as most of the witnesses summoned from the Philippines have refused to come to Hong Kong to testify.
The incident has strained ties between Manila, Hong Kong and the Chinese government.
The Hong Kong inquest is expected to last 25 days and will provide forensic evidence into what happened on 23 August when the former senior police officer Rolando Mendoza forced his way on to a tour bus.
The hostage drama lasted for 11 hours and eight tourists were shot dead.
On Friday the Philippines Department of Justice said that 72 of the 116 witnesses who were asked to give evidence in a Hong Kong court refused to testify and a number of key officials will not be present, including the mayor of Manila and the senior police officer on the ground.
But the court is setting up a video link in the hope that some will testify from Manila.
The way the police handled the attack came in for much criticism, as did the Philippines President Benigno Aquino in what constituted his first international crisis.
The police operation, the conduct of the city's mayor and that of the gunman's brother, whose arrest led to Mendoza beginning to shoot, led to many questions being asked here about how it all could have gone so wrong.