President Benigno Aquino III vowed Thursday that “someone will pay” for the bus hostage crisis that killed Hong Kong tourists as senators began grilling senior police officers over the deadly fiasco. Addressing students and teachers at a suburban university, Aquino said the nearly 12-hour hostage-taking drama Monday was “ghastly” and admitted there were “many failures,” but stopped short of directly blaming the police. “What happened should not happen again,” he said.”Someone failed, someone will pay.” At the Senate investigation, Manila police chief Rodolfo Magtibay said he gave the order to assault the bus carrying a Hong Kong tour guide and 20 tourists after hearing shots following a breakdown in the negotiations with the hostage-taker. The man, a Manila policeman who had been dismissed and was demanding reinstatement, released several children and elderly hostages early on, but later opened fire on the remaining hostages. Eight people were killed before a police sniper took out the gunman. Aquino and other officials have promised a full investigation. Interior Secretary Jessie Robredo, who is in charge of the national police, has acknowledged there were problems with how the crisis was handled, including inadequacies in preparation, equipment and training. Magtibay has taken leave and four leaders of the assault team that eventually stormed the bus have been relieved pending an investigation. Officials have said the firearms used by 200 police commandos will be subjected to ballistic tests to see if some of the hostages were hit by police gunfire. Magtibay told the senators that he “honestly believed” assurances by his assault team leader that they were prepared and were carrying the right equipment for the operation. However, Sen. Miguel Zubiri pointed out the police SWAT team did not have ladders or bus window blasters, and the rope they used as a makeshift tool to pry open the vehicle's door easily snapped. Another police officer testified that the team did not have a “flash-bang grenade,” a standard weapon used by police commandos to stun a hostage-taker. “It was Band-Aid solutions as we went along, but the element of surprise had already gone,” Zubiri said. “If you are a foreigner, you will no longer come to visit the Philippines because you have seen in the news that the police are not adequately trained.” The security committee of Hong Kong's Legislative Council was scheduled to hold its own hearing on the killings Thursday afternoon.