Prince Frederick was indeed murdered in Puerto Galera in the Philippine in 1994. It was probably a contract killing over either a yacht or a drugs deal. A certain Englishman long resident in the Philippines, with a checkered career, who dealt in yachts and arms was rumoured to be behind the deal but was conveniently out of the country at the time. He was subsequently picked up in Hong Kong on other charges that looked like a set up to get him given they couldn't prove his involvement in the Frederick affair. He was jailed in Stanley prison in HK and transferred to the UK before the handover to China. He was subsequently released and is back living in the Philippines.