Sherlock: The skeleton you see lying on the floor is that of John Jones Mcfarm. Judging from the state of decay through which lenghts the body has turned into a skeleton, it is presumed Mr. Mcfarm has been dead for atleast 1 month. The lack of blood indicates that Mr. Mcfarm has not suffered any physical traumas and there are no signs of violence. So Mr. Mcfarm either had a hearth attack, choked or got poisoned. However, from the evidence it becomes quite clear that Mr. Mcfarm got murdered.
Watson: And the cat thing?
Inspector Lestrade: But there is water all over the floor. Don't you suppose this water would have vaporized during the time it took for the body to decompose? This water was not here when Mr. Mcfarm died and someone was in here recently! And what cat thing...?
Sherlock: Ohyes the cat thing. I noticed that too. Excellent observation Watson. And isn't it obvious Lestrade?
Inspector Lestrade: No it isn't. How did Mr. Mcfarm die?
Sherlock: Don't you see? It was the cat!
Watson: That is not quite what I meant with the cat thing but eh.. do you seriously suggest a cat killed him?
Sherlock: Well not directly. You see, Mr. Mcfarm was a business man, and a pretty bad one actually. However he did get his hands on quite a bit of money before his death. You can see his brand new TV and computer. How did he get this money? Well it's quite simple. From what his daughter Macy Mcfarm told us, John here is quite the gambler. You see every tuesday night he would go out with some friends to play some poker, which is most likely how he got the money. But as you know with poker people aren't always happy when someone else wins. So in an attempt to get the money back, one of his poker buddies poisoned Mr. Mcfarm so that this friend would get his money back. And this is where the cat comes in. The poison was put on the cat, so that when Mr. Mcfarm would touch the cat, he would get the poison on his hands and sooner or later would get it ingested somehow. Thus ending Mr. Mcfarm's life.
Inspector Lestrade: So we should be looking at one of his poker buddies! That still doens't explain why there is water on the floor though.
Sherlock: No need for that, I got it all figured out. You see the poison used was a very delicate one. It can only be made by the finest animal biologist. I checked Mr. Mcfarms facebook page to look for any animal biologist and found only one. Casey Mcbane. If you go to his lab you'll find some samples of the poison used on Mr. Mcfarm. This should be enough to take him in and get a confession out of him. Oh and the water and glass? That was Peter the security guard who dropped two glasses of water when he walked in and found the body. He didn't tell the police because he has been doing it with the maid in guests their rooms, which is why he had two glasses of water. Too afraid he might get fired he didn't tell us.
Long story short: Poison killed Mr. Mcfarm. The water and glass comes from Peter who dropped two glasses when he found the body and lied about it to the police.