Ever wondered how forensic scientists figure out how old someone was just by examining their bones? It’s like something out of a mystery novel, but in the world of forensic anthropology, it’s a common—and fascinating--practice. This is the first in a series of blogs looking at what you can (and can’t!) tell from a skeleton.

Growing Pains: Childhood and Adolescence
When we're young, our bones are like puzzle pieces that haven’t quite fit together yet. Forensic anthropologists start their age estimation by examining features that change as we grow.

• Dental Development: Teeth are incredibly telling. Kids get their baby teeth first, followed by their permanent teeth. By looking at which teeth have come in and their stage of development, experts can estimate the age of children and teenagers quite accurately.
• Bone Growth Plates: In younger individuals, the ends of long bones, like those in the arms and legs, have areas called epiphyseal plates. These plates gradually turn into solid bone as a person matures. By assessing how these plates are fusing, scientists can estimate the age, especially for teens and young adults.

We all leave fingerprints behind every day. Anyone who wears glasses or owns a mirror has likely needed to clean them off. No matter how often we wash our hands, a natural buildup of grease on our skin means that we can’t stop leaving fingerprints. It may be annoying to clean, but they can get criminals in a world of trouble.

Let’s talk about how law enforcement (and writers) use fingerprints to finger the culprits.

The History of Fingerprinting
People figured out early on that fingerprints are a good way to identify someone. Ancient civilizations used fingerprints as seals or signatures on important documents and contracts long before paper was invented. However, the idea of using fingerprints in criminal investigations didn’t happen until much later.

By Harri Blomberg - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=794690

The Total Station pictured above must be accompanied by one or more prisms mounted on a long stick with a back target (pictured below). You sight through the Total Station's scope to record the elevation and position of the prism. By taking multiple readings, you can recreate the crime scene later.

Most people think of death as an either-or proposition: you’re either dead or alive. I’m not here to dispute that (sorry, zombies!). Instead, I want to talk about what a body goes through immediately after death. These are known as the stages of death or post-mortem changes.

If you’re a mystery writer, you’ve probably written about a medical examiner or detective estimating the time of death based on some or all of these stages. Even if you haven’t, most people have heard the term ‘rigor mortis.’ In fact, that (and a few others) are the go-to ways for investigators to predict when the person died during the early post-mortem interval (up to 72 hours after death).

Welcome to the glittering world of forensic science, where solving mysteries is only half the fun. Ever wondered how forensic technicians make bloodstains at crime scenes light up like neon signs? Spoiler alert: it’s not magic, it’s Luminol!

So, what’s the deal with this glow-in-the-dark wonder? Luminol is a chemical compound that glows bright blue when it reacts with the iron in hemoglobin. In simpler terms, if there’s even a trace of blood on a surface, Luminol will make it pop.