The ' Body in the bag ' case.

gloswhite - how do we know Gareth wasn't plotting to do something highly seditious?

Good point, but if that was the case, I would have thought they would have sussed him fairly early, and removed him from the scene. The last thing they would have wanted was all this publicity, especially as they came out of it so badly. Also, why would they leave him in his own flat, and then let someone else find him? As you say, its going to be one of life's mysteries, (at least for us not in the loop).