A photo at a funeral gets shot, leaving a star-shaped hole in it. The next time the photo is seen, it has a round bullet hole, without the star points.
On full auto, a submachine gun can use up a ten-round clip in 2-3 seconds and a fifty-round clip in 10-15 seconds. Yet, the shooter at the funeral never once reloads even after nearly a minute.
The establishing shot of the limestone facility shows a tractor operating on the premises, even though it's supposed to be abandoned. Also, the SWAT team approaches the building from between two piles of sand, but there are already footprints present, revealing at multiple takes.
When Horatio is calling in the shooting at the cemetery, he neglects to say that the suspects are escaping in a hearse. An essential piece of information the police would need to find and stop them.