A uniformed police constable jumped to his death yesterday in Yuen Long - taking this year's police suicide toll to seven. Ling Kim-chiu, 28, was critically injured when he jumped from the roof of the five-storey Yuen Long police station at about 3.30pm. He died about an hour after being admitted to Tuen Mun Hospital. Ling, who joined the force at 19, had served for about 10 years. He was married with a six-month-old boy. A police source said Ling left a note addressed to his wife saying stress at work had driven him to take his life. Ling's wife, who declined to be identified, said last night her husband had been unhappy since a 'demotion'. Ling recently found himself confined to desk work in the report room. The chairman of the Junior Officers' Association, Sergeant Lau Kam-wah, said some officers were under heavy stress at work. Confirming the suicide, Yuen Long District Commander Trevor Oakes said the cause was being investigated. On Thursday, Sergeant Ip Tak-yan, 35, attempted suicide when he jumped from the roof of the four-storey police married quarters in Fanling following a dispute with his 30-year-old wife. Three of the suicide cases involving police officers this year were related to gambling debts. There were 202 police officers with unmanageable debts in the second half of this year, with the officers owing an average of $530,000, according to the latest survey on the problem.