Most of these guys went out with friends, got separated from them at bar time and disappeared.
The only thing that indicates any foul play is that all the drowning victims fit the same profile.
At least several drownings involved somewhat lengthy walks to the river and drowning in shallow(er) waters - 3ft deep or so. Friends who are familiar with the area and the bar scene there believe there would be a tremendous amount of effort exerted for a drunk kid to drown in the way reported - as accidents.
Something's not right.