Pauley Perrette, who plays Abby, actually graduated from college with a degree in Forensics, and then moved to New York to get her master's, and it was there that she got in to acting, before coming to NCIS. Producers have said that most of the personality and interests displayed by Abby come from Perrette just playing herself.

When analyzing shell casings, there's more than one reference about the fact that it "could be either a Glock or a Beretta". The difference would be readily apparent to an experienced observer. Glock: the firing pin leaves on the primer a distinctive rectangular mark plus, in many cases, the extraction leaves a mark near the mouth of the case. Beretta: they leave just a small mark on the primer left by the percussion pin. There's no way you can mistake a Glock and a Beretta, given a spent casing fired from either pistol.

This definition appears in the opening credits of season 1; The Naval Criminal Investigation Service [NCIS] is a worldwide federal law enforcement organization whose mission is to protect and serve the Navy and Marine Corps and their families. To counter the evolving threats NCIS has implemented a new proactive strategic plan which emphasizes the following priorities; -Prevent terrorism and related hostile acts against DoN forces and installments -Protect DoN systems and information against compromise -Reduce criminal activity and mitigate the impact on Navy and Marine Corps operational readiness

The original pilot, a 2-parter in JAG, was re-cut into a single-episode and shown in the middle of the first season.

Edited from The Presidio (1988)