So that’s not the official word, but it’s getting pretty close. And a second season of the show seemed pretty much set within the planning of the first, as the season finale left a whole bunch of unresolved cliffhangers in its wake (spoilers ahead):
For starters, you had the bullied photographer Tyler first buying a gun from a contact, and then later revealing his Columbine-level secret stash of levels in his room; both things never followed up on, and presumably a set-up for Season Two.
Then we are given the news that musician Alex was in the hospital with a gunshot wound to the head—and an earlier image of someone being rushed in an ambulance. But we have no definitive confirmation that a) Alex tried to commit suicide, which was assumed b) the person in the ambulance was Alex.
And towards the very end of that last episode, Tyler is seen in his darkroom cryptically removing Alex’s picture from a creepy image collection of all his classmates.
So it would seem that most likely the second season would focus on Tyler getting revenge on the other students, perhaps picking them off one-by-one Scream-style.
And then perhaps instead of 13 Reasons Why, it might be 12 Reasons Why.
Such a “ripped from the headlines” plot would presumably maintain 13 Reasons Why’s status as currently Most Controversial Entertainment For Teens At The Moment, though one assumes that was going to be the case anyway.