So, my theory:
The original/second Prodigy that's been hinted at in X-Factor shows up at the Gala/on Krakoa. Magneto, realizing what this could mean to the concept of resurrection, kills either the original or newer version. He attempts to do it secretly, but gets caught somehow. So, not only is it a trial of Magneto for killing Prodigy, but also an attempt to keep the reason why a secret, because of what could happen to Krakoan society that death/resurrection isn't so clean cut. The fractures in the Krakoan society start with this.