We have analyzed all the evidence on the Stoppel case and noticed something interesting. We mapped out the entire murder and all the locations Arnold was seen before and after. The three points on on the diagram below connect to form a triangle explaining a possible escape route. 

      Our correlations are as follows:

•             From the location of Arnold's third floor window he had a clear view of the donut shop as well as Stoppel's walking route to and from work. 

•             Note that there is a walkway underneath the bridge that would make his escape quite easy as the path would have lead him home from there.

•             Someone unfamiliar with the area would most likely be unaware of the path. 

•             If he were to continue running across the bridge he would've been much easier to catch as the Norwood bridge is fairly long. 

      Could he have been planning this murder long in advance? Does it seem plausible that Terry Arnold killed Barbara Stoppel? With his criminal record he had definate motive to commit murder. With all the evidence pointing in his direction we're certain this man is guilty.