The Tomorrow People - Prime Factors

When Carol senses what she believes to be a new Tomorrow Person breaking out, she's excited at the possibility of a new addition to the team. However, when she, John, Stephen and Kenny discover that the person in question is the prime suspect in a series of mysterious disappearances in modern day Whitechapel, it raises dangerous questions.
Is it possible for a Tomorrow Person to break out without the Prime Barrier that prevents them from killing deliberately?
Or is there something even darker at work?