It seems we have a bit of disagreement between the barristers. See post 589 by jagusafr. :) Now, why am I not surprised. You guys are *worse* than engineers, and that takes some doing.
Certainly my memory could be off, but I recall that the proceedings were not particularly adversaral. It was about 1/2 day affair, maybe a bit less.
You could be describing an Admin Sep Board(for enlisted), or a Board of Inquiry(for commissioned officers). I didn't enter the JAG Corps until 1985, so they could have been called something different in the early '70s, but I don't believe they were.
Do you remember if the object of the your "panel" included the separation of the service member? If that's all that was at stake - no confinement, no reduction in grade, no forfeiture of pay, then you're definitely describing a Separation Board or a Board of Inquiry. They can certainly (and frequently will) be called based upon the conviction of a service member in a civilian court of law. If there's a criminal conviction in a civilian court, Admin Sep Boards are pretty straightforward. There's not much to argue, so it wouldn't appear adversarial, in the least - the service member was either convicted, or he wasn't. There's no "prosecutor" either. There's only the panel of officers, the service member, and his counsel, should he so elect (at his expense).
But, if your service member was facing additional charges that stemmed from a civilian conviction, Like an Article 86 spec, then at minimum, it was a summary court-martial.