In 2012, the Fairfax County Police Department handled a total of 16 homicides in the area -- five more than were reported in 2011.
Public Information Officer Lucy Caldwell said in a recent email 15 of the 2012 cases are already solved or closed.
In 2011, 11 homicides were reported.
Before then, the numbers vary: 16 homicides were reported in 2010, 14 in 2009 and 19 in 2008.
Caldwell said the majority of the homicides that happen in Fairfax County occur among family members, acquaintances or people who know each other — not between strangers.
A Fairafx County police officer found a man dead Dec. 28 in a car crashed off Chain Bridge Road, near Glengyle Drive.
Police believe Bonilla and the 19-year-old victim, Zavier O. Stringfellow, 19, of the Manassas area, had planned to meet up the night of the incident.
They met, police said, but there was allegedly a struggle during which Stringfellow was stabbed.