Eric and Glenn wrap up their “activity level series” by discussing two articles (Girod, et al. 2016; and Hinners, et al. 2020) which propose determination of aging of latent fingerprint residue. The techniques use instrumental techniques to identify breakdown products of various fatty components in latent print residue, and use these results to classify whether a latent print is a couple of days old, or older (up to a week or month old depending on the paper). This is a nice finale to the series to explore what the realities and limitations of aging latent prints entails, rather than relying on visual inspection and qualified “consistent with” statements that previous episodes revealed could be misleading or just plain wrong. Glenn also starts the show by relaying a little bit of his experience joining the new NIST/NIJ Human Factors Expert Working Group on DNA mixture interpretation.