A&E True Crime spoke to experts to explore the disturbing reasons why some men kill the person with whom they've vowed to share a lifetime.

How sound is the reasoning that a refusal to take a polygraph test is a sign of guilt? We speak to former polygrapher and current anti-polygraph activist, Douglas Williams, about what he sees as the test's fundamental problems.

Retired Detective Sergeant Joseph Giacalone had the pleasure of working with compassionate cops who truly loved the job and "cowboys" who were unworthy of the badge. Here are some of his stories.

We ask retired CSI detective Ken Martin about the legitimacy of TV cops digging bullets out of walls, tying red strings through a scene, and other forensic techniques to learn which are real and which are just for the camera.

Sgt. Sean "Sticks" Larkin, a member of the Gang Unit of the Tulsa Police Department, was a hit with Live PD viewers. Sticks answers our questions about how gangs took root and how to spot if your kid is involved.