It could just as easily point toward something going wrong as a result of everything taking place all at once, like someone involved betraying Gerald, resulting in his death and the death of others who would have become witnesses or would have gotten in the way.
It was more likely and much simpler to come to that kind of conclusion rather than thinking that someone else would have been involved.
Although there could be suspects who would be thought to be connected to it all, it would be less likely that they would gain as much attention from anyone looking into everything, just as there would be fewer things to connect them to it all.
It would be more likely that the people or person of interest to the case would be the more likely candidate or candidates that would have more of a motive to be involved in it all, and there would be some form of evidence that could point toward their involvement.
