An independent investigator is someone who looks into a situation or problem without any bias or vested interest. They are not influenced by anyone and can provide unbiased findings or conclusions based on their own investigation. Full definition
Soft - money positions are especially tough on those scientists who decide to go it alone as independent investigators. (sciencemag.org)
After the emails were stolen and published online, a number of independent investigators examined the conduct of the scientists who wrote the emails. (realitydrop.org)
So too have 65 of their trainees who are now independent investigators in the field. (americanasthmafoundation.org)