Formal defense investigator training programs only emerged in the late 1990s

Evidence

Investigators also develop their own language, much of it borrowed from law enforcement. This too can be a barrier to communication. For years, many criminal defense investigators were former police officers, and they relied on their police academy training. It was not until the late 1990s and early 2000s that more formal training programs for investigators were developed (see, for example, PI Now, 2019). Now, defense investigator students are taught a host of subjects, including civil liability, the history of defendants’ rights to competent investigations, evidentiary considerations, witness interviewing, ethics, the legal framework of privilege, process service, testifying, and report writing. The language investigators learn during this training helps them to, one, communicate better with attorneys and, two, better understand legal proceedings. — Joseph Avery, Jim Sidanius, Joel Cooper, Gregory Davis, Amanda N., Bias in the Law, 684