Let me say that the following researchers are totally serious about what they do. I also surmise that they are getting funding from government-related law enforcement orgs to pursue their endeavors.

Both have established hypotheses. Here’s 1). Materials commonly found at crime scenes can be profiled for bacteria to create a “unique” link to a perpetrators feet or most likely their shoes. So, its not really “poo” that they are studying. Its bugs from the environmentalal “microbiome.” That would actually be better, since poo may contain sloughed skin cells from the animal that could be subject to DNA testing. If you find Fido’s genetic material on a suspect, then maybe there might be a provable connection between the scene.  Unless the suspect is a dog walker. The microbiome arena is still hypothetical.

Article

2) Here’s the technical one about aging fingerprints from fat. This field of investigation has been around since the 1980’s. Here is a better news release with video from Phys.org.

Thus far I haven’t seen these on CSI.