I wouldn't say it was known to be a suicide mission. It was highly suspected, but the crew did have hope.
I have always thought this the most plausible theory because I think they underestimated the force of a pressure wave in a liquid. They basically depth charged themselves.
As Rabid is saying that release may be premature but that was exactly what the Huntley organization was saying two months ago. Now they are backing away from it some based on this US Navy analysis: