... There have been 22 homicides in the Prince William so far in 2016, compared to 10 last year. In many communities, the prospect of 22 murders in a year might not seem like a cause for concern. This year the District has so far tallied 134 slayings and neighboring Fairfax County so far had 18 homicides. But the numbers in Prince William County are the highest in the county since authorities began tracking homicides in 1975. The next most deadly year was 2006, when 16 people were slain. ... Experts attribute the increase to a range of factors, including...