The departure of executive committee members Bill Isaacson and Karen Dunn comes as perhaps the most damaging single blow to Boies Schiller Flexner, contributing even more uncertainty over how it charts its path forward, several sources familiar with the firm said.

Few in the firm had as much client business, or the kind of top-tier client reputation, as Washington, D.C.-based Dunn and Isaacson, who left for Paul, Weiss, Rifkind, Wharton & Garrison on June 11.