The Power of Six (I am Number Four Series, Book 2)

In the beginning, nine aliens left their home planet Lorien when it fell under attack by the evil Mogadorians. They scattered on Earth and went into hiding. They look like ordinary teenagers but have extraordinary powers. The Mogs have come for them. They killed Number One in Malaysia, Number Two in England, and Number Three in Kenya. They tried to get John Smith, Number Four, in Ohio—but they failed.