Brett Holmgren got woken up early on New Year's Day by alerts that a driver had plowed into a crowd of revelers in New Orleans.
The rampage, which killed 14 people, was the deadliest attack on U.S. soil in years and was inspired by the Islamic State group. The National Counterterrorism Center, which Holmgren leads, sprang into action to help the FBI run down information on the culprit from Texas and his plot.
