The body of a 19-year-old student was found floating in High Island Reservoir, Sai Kung yesterday, six days after he went missing. On Tuesday police mounted an air, land and sea search in the area, using tracker dogs, but found no sign of Tsoi Kin-hau. Sai Kung divisional commander Chief Inspector Lau Fu-wah said the swollen and decomposing body was discovered by Water Supplies Department staff when it floated to the surface yesterday. He said it was possible Tsoi fell or jumped into the reservoir before the search. "A preliminary examination found no external injuries on the body and an initial investigation found nothing suspicious," Lau said. He said police were still investigating the possibility of suicide. An autopsy would be carried out today to establish the time and cause of the death. One of Tsoi's relatives left a message on his Facebook page saying: "You chose this path. I don't know whether it's right or wrong. For you, it is probably a way to relieve yourself. Your departure makes a lot of people very sad." Tsoi's mother earlier told media that she believed her son was unhappy because of his studies. Police were called to the reservoir in Sai Kung Man Yee Road yesterday at about 9.45am after receiving a report that a body was floating in the water. Tsoi, a finance student at the Hong Kong Institute of Vocational Education (Sha Tin), was last seen when he left his home in Tak Tin Estate, Lam Tin on Friday. The next day, his mother reported him missing to police after finding a note left on his computer in which he asked his family to forgive him and not to be too sad. An air, land and sea search was mounted around High Island Reservoir on Tuesday after investigators learned Tsoi had wanted to go there with his schoolmates before he disappeared. Police had previously searched several of the student's favourite hangouts, but did not find him.