Quick rules summary: Ask any yes/no question, and I can only answer with one of these seven responses:
The Case - Easy
Wayne lies dead in the water, wearing a plastic raincoat.
The Mystery
Who killed Wayne, how, and why? How did his murderer get caught?
Was it Garth?
Is Wayne in a puddle on a street or sidewalk?
No.
EDIT: It feels so strange when you don't say Ronway.
No.
Is/Was Wayne a person?
Yes.
Is Wayne in a naturally-formed body of water?
Yes.
Is Wayne an adult?
Yes.
Was it raining when he died?
No.
Did Wayne drown?
Yes.
Was he held under water by the murderer?
No.
Did wayne drown of his own stupidity?
Define what you mean by "drown of his own stupidity."
Was he in the lake because of his own actions.
Define what you mean by "his own action." (Just so we don't go back and forth, you haven't determined what the body of water is.)
Did he trip and fall into the water. (Sorry, I'm trying haha)
No.
I think I see what Foote is getting at.
Was Wayne's death a suicide attempt?
If not, was Wayne his own murderer?
If not, was there a human agent that murdered Wayne?
Are you sure it wasn't Garth?
Was the water flowing?
No. Yes and no. Yes.
No. 
Yes.
Is the water outside?
Yes.
Was it a river?
Yes.
Did he slip on a rock?
Was Wayne intoxicated, perhaps from too much partying on?
No.
No.
Was anyone besides Wayne involved in his death?
Was Wayne's murder premeditated?
Had Wayne met the murderer previously, i.e. on some other occasion before the murder?
Yes. Yes.
Yes.
Was the murder out of anger?
Yes.
Was Wayne knocked out before drowning?
Was the rain coat stolen?
Is the fact he was wearing a raincoat of significance? If so, was he wearing it properly (ie the right way round, and not, I dunno, tangled up it it somehow, or whatever)?
Did Wayne voluntarily put on the raincoat?
No.
No.
Yes and no. Yes.
Yes.
Did Wayne try to avoid drowning, ie struggle or fight or swim?
Please rephrase your question.
Did Wayne know he was going to be killed before the murder occured?
No.
Did the murderer drown?
No.
Does the raincoat belong to Wayne?
Does it belong to the Murderer?
No. No.
Is the owner of the raincoat significant?
Yes and no. This goes back to whether the raincoat is significant. Tou can solve the problem without knowing about the raincoat, but it can also help you find out the answer if you know about it.
was Wayne murdered by someone he thought was an ally?
The scenario I'm thinking of is that Wayne and his killer were both involved in killing a third party. The raincoat was to block the blood spray or whatever. Then he was betrayed, and dumped in the river along with the guy they were trying to dispose of.
Yes. No.
Is the owner of the raincoat a woman?
I don't know/Irrelevant.
Is there someone else involved in this scenerio besides Wayne and the Murderer?
Define what you mean by "involved."
Someone that is family, spouse, ect. with either Wayne or the murderer that may have caused this murder to take place because of their relation?
Yes.
Is this third person a woman?
Is they are a women, is she married to the murderer?
Yes. No.
Was jealousy a motive for the muder?
was Wayne the intentional target for the muder?
Hmm...
Is she married to Wayne?
Is she having an affair with the murderer?
Yes. Yes.
Yes. No.
Is the murderer a woman?
Was Wayne having an affair with the murderer (regardless of the answer to the previous question)?
Is the murderer married as well?
Yes. Yes.
No.
Is the murderer friends with Wayne and his wife?
Did Wayne drown in a deep part of the river, at least waist high?
No.
Yes.
Did he attempt to swim to safety?
Yes.
Did he actually know how to swim?
Yes.
Did the raincoat contain something of value?
No. (Well, except for Wayne.)
Do we have a toxicology report on Wayne? (Was he drugged?)
Did something impede his swimming ability? Or did he stop swimming due to exhaustion?
No, he was not drugged.
Yes. Define "exhaustion."
Was there something in the pockets of the jacket he was wearing that impeded his swimming ability? (e.g. rocks)
No.
Yes.
EDIT: Sorry modifying this a bit. Changing it to: Yes and no. It was part of the problem, but not the only problem.
Was he unable to continue swimming because he was too physically fatigued?
Was the river bank too far away for him to reach by swimming?
I don't know. The story doesn't mention that as an issue, which means it probably wasn't.
Was the murderer jealous of Wayne because of his wife?
Are Wayne and the murderer old friends, like high school buddies?
Are Wayne and the murderer coworkers?
Yes. No. No.
Did Wayne's wife know that the murderer was going to kill Wayne?
No.
Did Wayne and the murderer live close enough to eachother that they could meet easily?
Was Wayne murdered in the city (or surrounding city) that he lived in?
Did the murderer know that Wayne was married?
I don't know (this means the story didn't say). No. Yes.
Was he out on a vaction when he was murdered?
Vacation out of the Country?
If so, was it with his wife?
Did the murderer just show up if he was on vacation with his wife?
Did he go with the murderer instead of his wife?
Yes and no. Yes and no. No. No. Yes.
He was murdered outside of the Country?
Would it be cheating if a looked up reasons to wear a raincoat by a river?
Ok, I have to declare a bit of my own lack-of-knowledge here, even though it may give away some clues. The story doesn't say his country of origin, but it does say where he was murdered. So, I don't know if he went out of the country. Now, of course, the next few questions will be: was he murdered in US, in XXXX, in YYYY. However, I really don't know. WE are dealing where very fine points about where the border is, and I just won;t know the answer. So, I will give this away: It is on the border of two countries.
I don't think so.
I know you said that Wayne and the murderer aren't old friends, but are they friends?
If they aren't friends, are they just casual acquaintances?
Yes. No.
Alright, I found 2 things.
Were they standing in the river fishing?
Were they at a waterfall?
No. Yes.
Did the murderer push Wayne into the river?
No.
Did the murder tell him to jump into the river?
Is the murderer related to Wayne?
Is the waterfall Niagra Falls?
Define what you mean by "tell him to jump in the river."
No. Yes.
Ohhh!!! I think I may of picked up that whenever you say define, it means it is close.
My original meaning was she litrally said "Jump into the river".
Dang it, I think you are on to me. It is so hard answering with only those reposnses, and sometimes the questions can mean so many different things, that you need the person to narrow down what the exact question is. Anyways, to asnwer your question: No.
Did the murderer force Wayne into the river by gunpoint?
Excellent. So between defining him getting killed by his on stupidity and her telling him to jump off, I think she told him to step somewhere that he foolishly listened to, which caused him to fall to his death.
Something I have done (not to the point to cause death...) with a camara before, causing people to trip over things. Since they are at a waterfall, it certainly makes since her to try to get a picture in.
So was she taking a picture of him and asked him to step back where he ended up falling into the river below?
If that's correct, we now only need the why and how she was caught.
Did someone see her do it?
Did she actually take the picture when he was beginning to fall?
Did she want him to leave his wife to marry her instead, when he declined is when she decided to murder him?
No.
Was the gender of the murderer ever confirmed?
Is the murderer male?
Yes.
No.
Yes.
Yes.
Wow! I think that is everything. Good job, everyone!
No. No.
Can we get the completed text?
Also, I think technically he died of something other than drowning... even if the official thing says otherwise
I don’t have the card with me, but it went something like this:
Wayne told his wife he was going on a business trip, but was really meeting his girlfriend at Niagara Falls. It was at that time that Wayne told his girlfriend that he was not going to leave his wife and that their relationship with as coming to an end.
The girlfriend was angry and decided to kill Wayne. They went to a secluded place above the falls, and she told Wayne she was going to take his picture. As Wayne was posing, she kept telling him to back up, until he fell into the river. He then went down the falls and drowned (although I agree he might have died for other reasons).
The girlfriend made one mistake, she actually took the picture of Wayne falling. When she got the film developed (remember 1993), the developer saw it and called the police.
So, what your saying is Garth was not at all involved?
I'm as shocked as you are.
So the raincoat was to protect Wayne from the spray from the fall.
Yes.
But if he didn't fall, it would have done nothing. :D