From Halopedia, the Halo wiki
During the Battle of Sargasso, on September 21, 2546, Pham and Gamma-Six was sent to the town of Belisk to protect Lethbridge Industrial's latest military-grade munitions manufactured for the Office of Naval Intelligence. While Pham and the squad protected the facility, ONI tasked another ODST squad, Alpha-Nine, with retrieving the facility's research data before the Covenant did. Unbeknownst to Pham and the rest of Gamma-Six, ONI had intended for the squad to serve as a mere distraction to allow Alpha-Nine to recover the data. Shortly thereafter, Pham was killed in action and Lance Corporal Sarah Palmer had taken control of the remainder of Pham's squad.
Given her surname, it is likely that she was of Vietnamese descent.
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