A Chinese court ordered a delay in the trial of four farmers accused of killing three people and blaming the deaths on mining accidents, prosecutors said.The trial began and then was recessed this week pending further investigation, China Daily reported Friday.\"This is a complicated case, so it could take time for the court to study all the evidence at hand,\" a court official said. No date was given on when the trial will resume.Prosecutors said the killings occurred at illegal coal mines.The defendants are Huang Yucai, 52, his nephew, Huang Xianzhong, 41, Zhang Xihua and Shiu Xuesong, China Daily said.They are accused of killing the victims to extort money from mine owners.\"In the first incident Huang Yucai\'s brother-in-law, who was mentally challenged, and his cousin were killed,\" said Han Xiujie, a police officer. \"The [other] victim was Han Junhong, Zhang\'s husband.\"The report said court documents show two of the three victims were killed in 2007 near Beijing and the third in July 2009 in the capital\'s Fangshan district.Police said the victims were hit on their heads with a hammer or a heavy tool at the mines. Prosecutors said the suspects then removed supports from a mine shaft overhead to cause a collapse.The report said police detectives persisted with their investigation to bring the case to trial after the four accused had received compensation from the mine owners.