Tom DeSena and Junior Lallbachan, experienced biohazard and crime scene cleaners popular on TikTok, tell us about their unique line of work.

Barbara Butcher, a former New York City death investigator, on what the work entails and which cases have stuck with her decades later.

In today's world, homicide detectives are expected to be jacks-of-all-trades: equally adept at chasing outlaws and identifying DNA evidence at the scene of the crime. But, in an overwhelmingly male-dominated field, Frances Glessner Lee, a Midwestern woman without a high school diploma, made contributions throughout the 1930s and 40s that earned her the moniker 'The Mother of Forensic Science.'

When new evidence arises, or new technology becomes available, investigators may need to take a second look at a corpse.

The true crime audience skews largely female, sparking some to question why the genre is so popular among some women. But in Rachel Monroe's book 'Savage Appetites,' she reverses that gaze, turning the lens toward four women who she thinks embody or challenge four classic archetypes of the genre: Detective, Victim, Defender and Killer.

Neal Smither, the founder and president of Crime Scene Cleaners, has cleaned up "thousands" of crime scenes. He's documented the work too, posting the gory images to an Instagram page that's attracted hundreds of thousands of followers. He spoke with us about his peculiar brand of janitorial work and why some people are interested in crime-scene photos.

Dr. Thomas Andrew, a medical examiner, says performing autopsies helped him understand the 'fragility of life.'

A&E True Crime spoke with forensic podiatrist Dr. Michael Nirenberg to learn about the differences between footprints and fingerprints and why foot evidence can be so valuable to law enforcement.

Some criminals get their crimes tattooed on their bodies, write 'fictional' books detailing murders they've committed or turn their own wanted posters into profile pics on Facebook.  We talk to an expert to better understand why some criminals implicate themselves in their crimes by communicating about them.

In recent years, hair, blood, saliva, and other bodily fluids from dogs, cats and birds have helped solve several violent crimes in the U.S. and Canada. A&E True Crime profiles four instances where animal evidence helped convict a criminal.