csi basics. take twitchell's garage for instance. this is what it looked like during the normal light of day. and this is a photo taken from the same angle minutes later once the floor was sprayed with aluminum all, the chemical that makes blood glow. >> huge spots in the garage which would indicate a large pulling of blood. they found a piece of a human tooth in the garage. we found blood splatter all along the walls. the garage doors. hundreds of spots of splatter where an obvious beating had taken place. >> also in the garage? csi and vested gaiters found this big gang processing kit. >> kitty hunters would take out and push to cut up a moose or whatever they've killed to bring him out. this is what he used and every single tool in that kit had our victims dna on it. >> and in twitchell's car, police found other hard evidence. >> we find a knife in their. a knife with blood on it.