A recruiting agency that is suing Simpson Thacher & Bartlett for withholding a placement fee on a lateral partner now says its alleged damages have expanded, based on learning that the law firm may have paid the partner a $1 million signing bonus.

Boston Executive Search Associates, a recruiting firm in Cambridge, Massachusetts, sued Simpson Thacher last December to recover a placement fee when Michael Torkin, previously a partner at Sullivan & Cromwell, joined Simpson Thacher’s restructuring practice.