the killer

 In the city of hong kong, there was a mass murderer, the man worked in opera theater, and there had died many peoples.The man were the owner of the opera academy. The firts case is: a  famous singer was killed while she is practice her perfomance on the scenary, fell the ceiling lamp,  the police was looking for some clues, they had the suspicion of someone very close of her., but the police didn`t found evidence 
the secretary of the academy  suspected of the owner, because in that day , she saw a knife in his hands.
the man knew that the secretary suspited of him, so, he decided to kill, in her house, with a stone in her head.
but the woman isn`t died. she is injured. she is taken to the hospital . when the police ask question her. she said that the owner academy was the guilty, so the man is led to jail to life imprisonment.