Murder in the Hotel

You are a detective, One day your are called for a murder case in a hotel. When you reach the place of murder you see a man dead, with a gun in his left hand and blood all over the place. The suspects and the people present at that time were The receptionist, the chef, the server and the cleaner. You enquire them one by one. First comes the receptionist when he was asked all he knew about the man, he said that all he knew was that the man came to sign for booking a room and payed him money from a suitcase, and it was all proved to be true after you saw the security camera footage, next you went to enquire the chef, he said that the man came and talked with him and ordered a cup of tea to his room and forgot his suitcase while talking to the chef and so the chef sent tea and the suitcase to man through the waiter. Next you enquire the server he says that he gave the tea and suitecase as the chef told him and he also said that the man quickly went to sleep after drinking the tea, so the server told the cleaner to clean the room later cause the man was sleeping. At last you enquire the cleaner, the cleaner says that she went to clean the room in the morning but when she entered the man was dead on the floor with a gun in his hand and the whole room was empty. After talking to all of them who do you think killed the man ??