[Spoilers] A question regarding Yuki (Answered)

I just finished SteinsGate 0. Good anime I should say though there are some questions which still bothers me: Back in episode 6 the group was once again attacked by a mysterious group. Suzuha managed to kick one of them on the wrist but since the attacker was wearing a bike helmet we couldnt figure out who it was. The next episode showed Yuki mysteriously having an injury: 500https://i.ur.com/8yJWNLP.jpg This sort of coincidental injury happens again in a later episode. I dont think it was addressed again in the anime or maybe I was just not paying attention much but was Yuki really part of the mysterious group? Professor Leskinen did say towards the end that he planted spies to infiltrate Okabes group beforehand.