Mr. Merrill joined the FBI as a forensic scientist in 1991 and was selected as a special agent in 1994. His first assignment as an agent was to the San Francisco Field Office, where he worked on the investigation and prosecution of Unabomber Theodore Kaczynski and also conducted public corruption investigations.
In 2006, Mr. Merrill served as an acting supervisory special agent at FBI Headquarters as a Department of Justice advisor to the Committee on Foreign Investment in the U.S. He was promoted to assistant legal attaché to New Delhi in 2007 and was the first FBI agent to respond to the 2008 Mumbai terror attacks.
Mr. Merrill supervised public corruption, civil rights, and antitrust investigations in San Francisco in 2010. He resumed work as assistant legal attaché in 2013, this time in Manila, Philippines.
In 2017, Mr. Merrill was promoted to assistant special agent in charge in the Boston Field Office, where he managed white collar crime matters in Maine, Massachusetts, New Hampshire, and Rhode Island. He also managed the forensic accountant program and oversaw the Varsity Blues college admissions case and the Insys Therapeutics health care fraud case.