Switchback

The Bureau of Preternatural Investigations returns in Switchback, the sequel to Melissa F. Olson''s Nightshades.
Three weeks after the events of Nightshades, things are finally beginning to settle for the Chicago branch of the BPI, but the brief respite from the horror of the previous few weeks was never destined to last.
The team gets a call from Switch Creek, IL, where a young man has been arrested on suspicion of being a shade.
The suspect is held overnight, pending DNA testing, but seemingly escapes in a terrifying and bloody massacre. But is there more to the jailbreak than a simple quest for freedom?