Snipped.
Clint very well may have killed Brian. Others have suggested that Clint may have been sexually obsessed with Brian.
Picture this: Clint has been lusting after Brian for years, and now that Brian's mother has died, Clint thinks to himself, "Brian is vulnerable now and is open to being comforted by someone; I could be that someone." At some point during the evening, the two friends are sitting at a table in one of the bars, and Brian confides in Clint, telling him that he isn't sure that he (Brian) is ready to get married. Clint is ecstatic and thinks, "Time for me to make my move--it's now or never." He says, "I'm here for you Brian--I've always been here," and runs his hand up Brian's thigh while leaning in to kiss him on the mouth. Brian is completely freaked out and gets as far away from Clint as possible. He has no idea how to process what just happened, but then he remembers that it's April Fool's Day and convinces himself it was a joke--or maybe he knew about Clint's sexual proclivities but blames Clint's behavior on the alcohol. Later in the evening, at The Angry Tuna, Clint pulls Brian aside to talk about what happened, asking him to step outside through the service entrance leading to the construction site so they can have some privacy. Brian agrees because he mistakenly thinks that Clint is going to apologize, but Clint is thinking, "He needed a moment, but now he'll give in." As soon as they get to the construction area, Clint makes another pass at Brian, attempting to kiss him. Brian is appalled and goes off on Clint, perhaps calling him some derogatory names, not hiding his complete and utter disgust. Clint is humiliated and attacks Brian on the spot, hitting him on the head with something left at the site, such as a two-by-four, or maybe just pummeling him with his bare fists. Clint's rage dissipates after a moment, but it's too late: Brian is already dead. Clint thinks fast, wrapping Brian in a tarp that he finds at the scene and heaving Brian into a construction dumpster. Hiding his homosexuality for years has made Clint a good actor, so he reenters the bar and rejoins his female friend as if nothing happened, pretending to be looking for Brian. After the bar closes, Clint heads to Brian's apartment in an attempt to further present himself as baffled by Brian's disappearance. The oddness of his behavior makes some people suspicious, but luck is on Clint's side in that the construction dumpster is emptied early Saturday morning, before Brian has officially been reported missing.
That's only one way things could have gone down, but some variation of that chain of events is Occam's razor in this case.
First I want to commend you on your writing creativity. Honestly and I mean this as a compliment if I didn't know anything about this case I would think I was reading a romance novel.
So the short version, Clint could not have killed Brian because after Brian stepped back into the bar at around 1:52 am both him and Meredeth said they waited for him. So Clint never left Meredeth and even if he did there would never be enough time for Clint to do all that you have suggested. Plus Meredeth took a lie detector test and I would guess that the police asked her detailed questions about that night especially ones about Clint. Stuff like, after Brian went back into the bar where did you and Clint go? At any time did you separate from Clint? Did you and or Clint try to call Brian?
Clint did mention to the police that he tried to call Brian. I'm sure they checked his phone records. If his call was on the earlier side of 2 am then it had to be before he supposedly killed Brian as he would most likely been in the middle of cleaning up his mess and not have time to call during a clean up. Also the police questioned the band and we don't know what time exactly that Brian talked to them or for how long but the police would at least have a good estimate as to how long. This would also shorten the time line for Clint.
If I remember correctly Clint said that he went back into the bar and looked around and even went into the restrooms. I would say that Meredeth could verify this. One way for the police to find out stuff about Clint would be to ask Meredeth. Either she says yes, no or I don't know but either way they at least get some of their questions answered.
Brian was last seen out in the hallway very close to 2 am. He told Clint and Meredeth that he was going to talk to the band. The stage is all the way at the other end of the bar. We can't even guess how long Brian was out of site from Clint and Meredeth but if one tries to put a time frame on this scenario I wouldn't know where to start.
How is it possible for Clint and Brian not to be seen by 2 policeman that were standing outside at the top of the escalators walking into a restricted area?
How did Clint know about the construction area to lure Brian there?
How would Clint and Brian navigate in the dark and they would have had to get all the way down to the first floor. The police said that it would have been very hard for Brian to navigate that area.
Why would Clint even suggest to Brian that he wanted them to go into a construction area well after 2 am that was off limits and was being more or less guarded by 2 policeman and while Meredeth was waiting? Why not just go home with Brian and talk to him there about the feelings that he was having?
Cadaver dogs searched the construction site. If Clint somehow was fast enough and lucky enough to find a tarp and somehow wrap up Brian into it and with more luck was able to find a trash bin that was empty enough to get him into this thing the dogs would have smelled death and I would imagine there would have to be a certain amount of blood.
Now after all this was done which would have to had been in a span of no less than 15 minutes he would have had to be able to get back into the building using that same entrance. Again he would have been seen by someone most likely the 2 policeman.
So here you have a very drunk man who's heart is racing because he just got done killing his best friend and on top of that he knew that he had just minutes to dispose of a body by himself. Brian was a big guy and dead weight is not easy to handle. He would have had to be sweating like a pig when he got back.
One last thing, we do not (unless I have missed it) know what time Clint and Meredeth left the building. They had to have left by 2:30. So in a span of 30 minutes he would have had to go find Brian convince him to leave the band during a conversation walk out of the bar down to the bottom floor through a construction area kill him, hide him get back into the bar with out anyone seeing him and then hook back up with Meredeth. That's assuming that they left at 2:30 but I'm not sure when they left. IF he was gone from Meredeth for the whole entire time why would she even wait for him? If she did then she would have most likely told the Police when she was questioned that she didn't see Clint for good amount of time. Unless she lied about somethings but she was given a lie detector test so I doubt she would lie.