Pickle King by Rebecca Promitzer

The town of Elbow is known for two things, unceasing summer rain and Herman's Pickles. Bea, 11, is a camera whiz, so when her friend Sam discovers a dead body in an abandoned house, he wants her to document the scene. She photographs the twisted, waterlogged corpse with its missing eye, but once she develops the shots, her camera begins to act strangely. It moves by itself, spins around, and emits weird groans. The dead man has evidently hitched a ride and now he wants the kids to investigate his demise. They identify the victim as the former head of the pickle company, now taken over by a big conglomerate. Furthermore, they learn that people tend to disappear in Elbow. Some end up in St. Agnes mental hospital, some turn up among the half-crazed outcasts in a filthy camp under the garbage dump and some just never surface again. Gradually, the friends realize that there is an even more fiendish scheme behind the disappearances and they may be the next victims. The young investigators sneak out late at night, drive a car, access restricted hospital files, and spy on a meeting of the villains' secret Brotherhood. There is plenty of truly gross action as well.