Murder in Evergreen by Jim Riley

The FBI send their newest agent, Wade Dalton, to interview a girl who turned up missing from Metairie. But when someone murders the girl in the room with Wade, everything in Evergreen changes.

Wade teams with the petite acting sheriff, Sam Cates, to investigate. Strange events take place in the small community, and Sam's father disappears. Things take a turn from bad to worse, and the team finds out that they're fighting an ominous foe with unimaginable resources.

Soon, the frightening truth behind the murder is revealed... and it's something neither could have expected.