Jay Nanavati, a partner at Kostelanetz & Fink in Washington and a former U.S. Justice Department prosecutor, formally joined Paul Manafort’s defense team Tuesday, becoming the latest tax specialist to sign on to advocate for the former Trump campaign chairman amid the special counsel’s Russia investigation.

Nanavati’s formal entry of appearance comes three months after prosecutors working under Robert Mueller III, the special counsel, brought bank and tax fraud charges against Manafort in the U.S. District Court for the Eastern District of Virginia. Mueller’s prosecutors first filed charges in Washington federal court accusing Manafort of financial fraud and failing to register as a foreign agent based on his lobbying work for Ukraine.