As she has for many years, Sonnenschein Nath & Rosenthal partner Lisa Murtha traveled to Las Vegas this past April to attend a conference of the Health Care Compliance Association, an organization she helped found. Joining her on the trip were three colleagues who had recently made the jump after her from Huron Consulting Group Inc. to the Chicago office of Sonnenschein. During the conference, the law firm hosted a dinner, inviting current and potential clients, including some former Huron customers.

That April 26 dinner at Caesars Palace is now a key piece of evidence in a lawsuit brought by Huron against Sonnenschein. The company is alleging that five former employees, including the four at the conference, breached agreements with their prior employer in pursuing business relationships with Huron clients and stole trade secrets related to Huron’s work. Huron also says that Murtha was the ringleader in recruiting eight employees to leave for Sonnenschein in the weeks after she resigned on Feb. 15, 2009, and in helping the law firm build up a rival health care compliance business.