From reading the report the board put out it sounds like it was information from a "confidential member" that tipped the scales for Mel's expulsion.

The report says: Confidential Club Member, (who wishes to remain anonymous, but whose identity is known to both Jim Reilly and Nate Pincus) has provided corroborating information that substantiates Dave Whalen’s version.

I'm not saying I agree with the board's decision but it has sounded like they want a third person besides Whalen and Porter. Perhaps they want another club memer because Whalen is not a member.