The hub caps on the Detroit Police car change from a turbine type to a full metal stainless steel.
When Floyd Tibbets and Mike Ryerson drop off the delivery crate at the Marsten House at night, Floyd checks out Straker's expensive car out of curiosity. From the outside he uses a flashlight to look at the interior through the windows and sees a small round package of some kind on the back seat. Floyd recoiled from the sight of the mysterious package which, the following day, he reports to Larry Crockett as being "head sized" when there is an ongoing search for the missing child Ralphie Glick. Crockett told Floyd it was likely fish that Straker had caught, but at the time Floyd first saw the package, Ralphie had not yet been reported as missing and there was no reason for Floyd to recoil the way he did and suspect that Straker had a disembodied head in his car (which it obviously wasn't anyway).
Since Mears is under arrest when brought to the hospital for the assault and attempted murder of Father Callahan, there should be police officers in his room guarding him, yet none are present.