TWO ransom demands have been made for the release of two former Hong Kong residents and a British tourist held by a breakaway group of the Khmer Rouge in Cambodia. The ransom notes were relayed to the Cambodian Government by Khmer operatives indirectly in contact with the captors, but authorities have been unable to confirm the notes are genuine or that the three captives are still alive. Attempts are being made to open negotiations between senior members of the Khmer Rouge and the Cambodian Government in an effort to have the three freed. At the same time a parallel investigation is being conducted into unconfirmed reports that the three have been killed and buried in graves near where they were kidnapped. Dominic Chappell, 25, his Australian girlfriend, Kelly Wilkinson, 24, and their British friend Tina Dominy, 24, were kidnapped on April 11 as they were returning to the southern port city of Sihanoukville from Phnom Penh. Mr Chappell's father David said yesterday that British Embassy officials in Phnom Penh had confirmed that ransom demands had been received on Tuesday and Sunday. He would not say how much money had been demanded in case it harmed future negotiations. The ransom letters were delivered by government field operatives who have been in contact with the Khmer Rouge through intermediaries. However, they have been refused direct access to the three, despite requests they be allowed to confirm they are alive. The letters are understood to have been brief but contained details of how much money was wanted. ''The ransom letters provide no proof that the three are actually held by the person claiming to have them and there was also no proof that they are alive,'' Mr David Chappell said. He said moves were being made through the Cambodian Ministry of the Interior and the British and Australian embassies to contact a leader of the main body of the Khmer Rouge to arrange negotiations. The Khmer Rouge commander holding the three is understood to control a small band of heavily armed guerillas operating in the rural south, away from the main Khmer Rouge forces in Cambodia's north-west. Cambodian Government operatives sent to investigate unconfirmed reports that the three were dead had yet to return. Despite rumours that the three had been killed shortly after their capture, Mr Chappell said that, based on other information, it now was reasonable to assume the reports were false. He said the ransom notes, if genuine, were a positive step towards seeing his son again. ''I'm not going to get my hopes up until I know for sure that they are alive,'' he said. An Australian Foreign Affairs Department spokesman said the Australian and British governments would not pay any ransom for their release. It must be confirmed the three were alive before any concrete talks could begin, she said in Canberra.