"Frankie, I think. He was right next to me, just making a joke, and then it was like something yanked him away. Yeah, it was him. Definitely him." -Winston confirming Frankie's fate.
Frankie was a former Glader who appeared in The Scorch Trials.
Biography
<tabber> Maze Runner= In The Maze Runner, Frankie is one of 21 Gladers who manage to escape the Maze. |-|Scorch Trials=In 'The Scorch Trials, Frankie was the first one killed in the tunnels by the Metal balls.