Plot hole: When Dex is doing the jack in the box ,he is hanging out the sun roof driving with his feet, using the cruise control. When he is decapitated, the body falls and the car spins out and stops. The car's cruise control was still on. The car should have kept going until the brake was pressed. Even if the body hit the brake on the way down, it would have coasted to a stop and not spun out and screeched to a stop.
Plot hole: The photographer who found the dead guy (Stalkerazzi) told Horatio that he was chasing a black Cadillac Escalade that was chasing the Stalkerazzi's car. He also said that he got stuck behind a truck and that when he finally caught up the Stalkerazzi was dead and there was no sign of the black Escalade. Throughout the rest of the episode nobody does any looking into the black Escalade, asks suspects if they own one or even mention it again. No investigation of the truck that the photographer got stuck behind was shown either. In the same episode Speed tells a cop, while in a tree looking into someone's yard, that they go in through windows if need be to close a case. This is totally inconsistent with the rest of the show and the law. They are always careful about getting search warrants and doing things By the Book.
Plot hole: Delko is rummaging in Speedle's locker. Why would Speedle still have a locker, considering he's been dead 3 years? Even if they couldn't allocate it to someone else, why are his personal effects (e.g. his wallet) still in there? Shouldn't these have been returned to his family?
Plot hole: The mother lets her daughter drive because she forgot her glasses inside the restaurant and cannot see to drive. This only makes sense as a means to move the plot forward because if she was still at the restaurant (which she would've had to be because she couldn't have driven elsewhere without her glasses) then she would've just gone back in to get them rather than let a 14 year old drive.
Plot hole: There is a large amount of blood found at Rachel Turner's apartment and it's determined to be Horatio's. He is subsequently arrested. Why wouldn't he be checked for a cut? To bleed that much would require a large cut and since it was only 24 hours it wouldn't have had time to heal, therefore proving that the blood although his had to be planted. That's too large an oversight by the police to just be a character mistake.
Plot hole: Delko pulls over Hayden early in the episode and questions him. Later on the shooter from the spa is found dead and he has glove markings on his arm. Delko tells Calleigh to compare the markings to the gloves he took off Hayden and they are a match. But Delko pulled Hayden over hours before he killed the shooter. If Delko had the glove in custody, how could Hayden have worn it during the killing?
Plot hole: There is absolutely nothing that would give Horatio any reason to think the severed arm they found was from a previous victim of their suspect. It doesn't make any sense he would pick something as random as the arm that has no connection (other than it being found during the search for the girl) to the case.