About the usage of the particle に


ダメだよ花咲、先生に見つかったら色々ヤバいんだからさ

So from what I understand the に takes the meaning of "by" only when used with
a passive form. That is when used with passive form the person/object etc
marked by に is the one doing the action directly or indirectly.

And when there's no passive form the action is being directed toward the
person/object marked by に.

In this case however there is no passive yet it still takes the meaning "by"

