Tenebris

And this time, it has left a witness. 

Jim Duchane watched it kill his two best friends. Now tormented by their deaths and skeptical of his own memories of that awful night, he is approached by two fringe monster hunters who are desperate to track the beast. With his help, they will hunt down a monster of Native American folklore whose very existence belies a terrible biological reality. 

And it may be the worse mistake Jim has ever made.