NEW YORK (AP) — One was a gambling addict who got plastic surgery to change his appearance even after his predecessor died from doing the same thing. Another claims to have begun his life of crime at age 4. A third was a kid from Chicago who made a fortune off of drug running.

The three — Tirso Martinez Sanchez, Jorge Cifuentes and Pedro Flores — now share the notoriety of being the most recent cooperators to testify against the infamous Mexican drug lord Joaquin "El Chapo" Guzman at a lengthy U.S. trial that's heading into an extended holiday break.

Painting a vivid picture of the Colombian-M...