- May 1 – 56-year-old Debra B. Anderson commits suicide in the Target in Burke.
- May 4 – 21-year-old Shelinda D. Arrington is run over and killed by 32-year-old Gloria A. McMillan when Arrington confronts McMillan on Harrison Lane in the Groveton section of Alexandria.
- May 12 – A ceremony is held celebrating the recent completion of several improvements, including a new playground, pavilion, and volleyball court, in the Mount Eagle Park in Alexandria.
- May 16 – 47-year-old Morgan D. Monroe, Jr. is shot to death in the Mount Vernon area of Alexandria.
- May 19 – Fairfax County Police fatally shoot 22-year-old Gray A. Combs, Jr. when he menaces them with a sword after they discover him hiding in a closet in an apartment in the 5700 block of Backlick Road in Springfield. Combs had been sought on charges of multiple charges of producing and possessing child pornography for taking nude photographs of his 16-year-old girlfriend with his cell phone.
- May 24 – A cooking fire mortally injures 91-year-old Carroll Adams in his second floor apartment at 1808 Old Meadow Road in McLean. Adams is taken to the Washington Hospital Center with third degree burns over nearly half his body, and dies the next day.
- Lawton, Beth, and Susan Larson. "Update: Shooting Reported At Burke Target." Fairfax Station Patch. Patch.com, 1 May 2012. Web. 20 May 2012.
- Fairfax County Police Department. Public Information Office. Suspect Vehicle Seized/Driver Arrested. Fairfax County Police Department News Releases. Fairfax County Police Department, 7 May 2012. Web. 08 May 2012.
- "Park Improvements at Mount Eagle Park." Connection Newspapers. Connection Newspapers, 11 May 2012. Web. 12 Oct. 2014.
- Farmer, Liz. "Police ID Fairfax Homicide Victim." Washington Examiner. The Washington Examiner, 19 May 2012. Web. 19 May 2012.
- Pennybacker, Gail, and Chris Van Cleve. "Gray Alan Combs Shot, Killed in Springfield." WJLA News. Allbritton Communications Company, 20 May 2012. Web. 11 July 2012.
- Bowman, Bobbi. "UPDATE: McLean Fatal Fire Ruled Accidental." Mclean, VA Patch. Patch.com, 25 May 2012. Web. 16 June 2016.
|Fairfax County by Year: 2012|
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