The Major Crimes Division, part of Fairfax County's Criminal Investigations Bureau, is tasked with the rigorous investigation of major criminal offenses ranging from murder, rape, and robbery to financial crimes and cases involving children. This division is the central investigative entity, receiving case referrals primarily from patrol officers, in addition to citizen reports and collaborations with other law enforcement agencies. Detectives within the division work in partnership with the Commonwealth’s Attorney’s Office to ensure successful prosecutions in the cases they investigate.

Supporting the division's efforts, the Property & Evidence Section is vital in managing the custody and preservation of all evidence related to criminal investigations. The Crime Scene Section complements this by specializing in the forensic examination of crime scenes, applying sophisticated techniques to gather, analyze, and interpret evidence. This scientific approach is crucial in unraveling complex cases and providing the necessary support for prosecutorial success. Together, these components underscore the division's commitment to meticulous investigation, evidence management, and collaboration, aiming for the effective resolution of serious crimes and the promotion of public safety in Fairfax County.

Sergeant Emian Underwood, has been a police officer certified through the Fairfax County Criminal Justice Academy since November 2018, From February 2018 to November 2018, Underwood received formal training on the criminal and traffic laws of the Commonwealth of Virginia, and the enforcement of those laws by issuance of citations seizure of evidence and making of arrests based on probable cause. Resulting in the conviction of numerous defendants for violations of the laws of this State.

In June of 2019, Underwood was assigned to the Criminal Investigations Division for the Arlington County Police Department. Emian Underwood's current assignment is a head investigator within the McLean District Station for the Fairfax County Police Department.

Emian Underwood is known for conducting criminal investigations, identifying, and enforcing violations of Virginia Commonwealth Law as well as the Fairfax County Code, testifying in court, preparing charging documents and making lawful arrests.

Emian Underwood is also a Veteran with the United States Army and has held the paygrade of an O-3 (Department of Defense Captain Paygrade), Underwood has served within various units, jumping from law enforcement, to military intelligence, to engineering. Underwood has held a Federal Civil Service General Schedule Paygrade of GS-13 while serving in the United States Army Criminal Investigations Division, after that, Underwood has served within the United States Army Corps of Engineers (ACE) at the U.S. Defense Department Paygrade of (O-3), and was stationed at Joint Base Myer-Henderson Hall in Arlington County, Virginia with the 3d U.S. Infantry Regiment (The Old Guard). She retired in 2010 from military service.