Gun violence is the leading cause of mortality among young black men and the county needs to treat it as a public health issue, according to Karen Hacker, director of the Allegheny County Health Department . “ How do we help to prevent this ?” Hacker asked. “And how do we help communities to heal because the impact of this kind of violence is really like post-traumatic stress in many of our communities.” She found an ally in the local Christian community.