You're wrong

I kind of stumbled across a tumblr post that was about the teachers finding Izuku's notebooks and thinking he was the traitor and I just .... my hand slipped. (and so did a couple of tears)
-----
It didn't take long before the dots were connected.

From quirkless, to having a very powerful quirk.

From friendless to having lots of friends.

From being quiet and withdrawn to being louder and outgoing.

All of that happened in the span of a year; the year he was enrolling in UA.

But, just like always, the villain makes a mistake, and that mistake is always what got them caught.

What was that mistake for Izuku Midoriya?

Leaving his most recent notebook open on his desk.