After Dean A. Zerbe resigned his post as senior counsel to Sen. Charles E. Grassley in February, the nonprofit world breathed a collective sigh of relief. The man responsible for the government’s sharpest scrutiny of nonprofit organizations was gone, and few observers believed his replacement would have the same chops.

Not so fast. This afternoon the Iowa senator, who is the top Republican on the Senate Finance Committee, announced Mr. Zerbe’s replacement: Theresa Pattara, a former IRS official who recently spent a year working closely with Mr. Zerbe on a variety of inquiries into the management and operation of nonprofit organizations. She also helped develop the IRS’s new 990 tax form.

A tireless investigator with strong convictions, Ms. Pattara, like her often-quoted predecessor, likes to speak her mind. She intends to follow the trail Mr. Zerbe blazed, continuing an investigation of college endowments and other nonprofit tax matters.

Mr. Zerbe has high praise for his replacement: “She’s smarter, better, and faster than me,” he said in an interview today. “Colleges and charities better pull up their socks and make sure they’re doing good.” —Brad Wolverton