Villain made from heroes

The Kamino incident

Once all the villains left the campsite police came to search thoroughly for any information left on the villains who escaped.

What they found was that Momo managed to place a tracking device on the Nomu, the fallen mask of the green hooded villain, and three villains who were left behind by the League of villains.

The remaining villains there were a knocked-out moonfish and a restrained Mustard with a broken gas mask.

Once they reached a mountain they noticed the deceased body of the third villain who was found next to the young happy boy who lived with the pussy cats.

The police believed that he was in shock but in reality the boy was extremely happy explaining to the police, "I was saved by him."

With that all the detective Tsukauchi had was two restrained villains who were unwilling to talk, a dead body, and the mask of one of the original members.

At first the man believed that he had nothing  on who the others were but then when interviewing the students he found out that one of the students, Shoto Todoroki, saw the face of the green hooded villain.

This was great information as the third villain from the USJ was the only villains who the police had little to no information about.

All he found out was that the hooded figure had green hair, green eyes, and the same age as the students.

This drew the attention of the detective as he felt that the identity of the Assailant was related to a missing person case.

Going through the file at the police station he saw it, Izuku Midoriya who recently went missing a few weeks ago.

He remembered the boy because All Might asked about the missing teen.

At this point the detective was beginning to connect the point between the teen and the villain.

The missing Izuku Midoriya was the green hooded member of the League of Villains.

He didn't know why but All Might was extremely interested in finding him, though telling the Hero that the boy was a villain would shock him, though he still needs to do it.

With that the detective had already called All Might who soon entered his office at which point the Detective knew that he would need to tell him about the boy.

"All Might, I found some information about the teen who you asked about."

The Hero had a smile, a smile which would be destroyed at what he was going to tell him.

...

Days after the attack and on every channel on the tv Izuku saw the same thing. 

UA failed to save two students.

Fumikage Tokoyami and Katsuki Bakugo

UA was explaining how their students were kidnapped by the league and how the school did nothing to save them.

Seeing this brought a smile upon Izuku's face as he realized that the league had won a victory upon the heroes.

Soon the smile disappeared as he realized that Mustard was now gone.

Muscular was going to be trouble from the beginning so taking care of him was easy for Izuku and Moonfish well, he could care less about him but Mustard.

He was the only one of those three who had actual conviction, being wronged by society and its hero system so losing him was a big blow to Izuku.

He knew the 13 year old wouldn't reveal anything but still having him there, both mind and quirk, would better the league's goals, a member who also believed in the truth of all their goals.