Killings Boost Vigilance as Public Officials Cope With Threats

Killings Boost Vigilance as Public Officials Cope With Threats

Ronald Martinez/Getty Images

The Texas state flag flies at half staff at the Margaret Hunt Hill Bridge April 4, 2013 in Dallas, Texas. The flag was flown at half staff on the day a memorial was held for Kaufman County District Attorney Mike McLelland and his wife Cynthia, who were shot and killed in their home about 20 miles east of Dallas.