I've decided one has to start out from assumption that he Brian didn't walk out of the building that night. Often it is legitimate to be skeptical of the work done in an official investigation. But in this case, the original investigators, who are closest to the facts and have the best information (including the video footage) have expressed such a degree of confidence in their scrutiny of the CCTV, I don't think there's any justification to second guess them. I get the impression the detectives sat in front of the video footage and scrupulously recorded the comings-and-goings, and for every entry in the left-hand column (meaning somebody entered the Tuna) they ended up with a corresponding entry in the right-hand column (the person left the Tuna), except for one entry: Brian himself. And evidently they involved Brian's family and friends to the extent that there were any uncertainties. Errors are definitely possible, but the original investigators would have been just as aware of that possibility as anybody analyzing the case today, so without some compelling new reason, there's no logical basis for doubting their work. I was thinking this especially when it comes to possibilities like that he took off the polo shirt he had on over his white tee shirt (discussed above in this thread). That's obviously a possibility, but it's just not the kind of thing the original investigators would have overlooked. I think it's practically certain that if a person was on the video footage, who fit Brian's description except for the fact that he was wearing a white long-sleeve t-shirt rather than a short-sleeve green polo over top of the same kind of tee-shirt, then it would have occurred to the original investigators that it might be Brian himself, having removed the top-layer shirt...
