A personal injury firm’s case that accuses a New York area competitor of paying clients out of a briefcase full of cash to switch law firms has escalated, with the plaintiff revealing that one of its paralegals went undercover as a potential client to obtain “forensic” proof of wrongdoing by William Schwitzer and his law firm.

Ginarte Gallardo Gonzalez & Winograd raised eyebrows last year with a lawsuit in Manhattan Supreme Court claiming that Schwitzer and his firm, William Schwitzer & Associates, used non-attorney “runners” to entice Ginarte clients in a doctor’s office waiting room to switch firms. The Ginarte firm revealed Friday that one of its paralegals pretended he was injured on a construction site and recorded conversations with the runners and two lawyers at Schwitzer’s firm.