Covington & Burling continued its hiring spree, adding former Homeland Security Secretary Michael Chertoff as senior of counsel.

Chertoff, who joined the Bush administration in 2005, will practice in the firm’s white-collar defense and investigations group, according to a firm press release.

Chertoff’s arrival comes after the firm has picked up several Republicans in recent weeks.

Earlier this month, former Oregon Sen. Gordon Smith (R) came aboard as a senior adviser. Covington also added Ambassador John Veroneau, who most recently served as deputy U.S. trade representative in the Bush White House.

Bill Wichterman also rejoined the firm after a stint as special assistant to the president and deputy director of public liaison.