Hong Kong forensic experts on Monday inspected the bullet-peppered bus in which a hijacker killed eight tourists in Manila last week, as the Philippines worked to calm China's outrage over the bloodshed.
Anger has been rising in Hong Kong since the August 23 carnage in which a disgruntled former Philippine police officer took the bus load of tourists from the Chinese territory hostage in a bid to win his job back.
Hong Kongers have blasted a failed rescue operation and botched negotiations that seemed to enrage the hostage taker, who was eventually killed by a police sharpshooter.
Organisers said about 80,000 people marched in Hong Kong on Sunday, denouncing the Philippines and demanding justice for the dead.
President Benigno Aquino III has ordered a thorough investigation into the crisis and the police response, and on Monday the Philippines allowed Hong Kong forensic experts to inspect the bus.
"We want to appease them and show that we're not hiding anything," Philippine National Police spokesman, Mr Agrimero Cruz, said.
"This is a show of transparency."
Guided by Filipino investigators, the Hong Kong team used flashlights as they looked at the bloodied passenger compartment, taking pictures of bullet holes and shattered windows. Another checked the bus tires shot out by police to prevent the hostage-taker from moving out of a police cordon.
The Hong Kong investigators refused to talk to a throng of Chinese and Filipino journalists.