Decorated Army Special Forces Master Sgt. Matthew Livelsberger had an 8-month-old daughter at home and a new assignment involving drones that friends said excited him. He wrote glowing Yelp reviews praising the tattoo parlor in his Colorado Springs hometown and touting the benefits of float spas. And when his father last spoke with him on Christmas Day, he told CBS News, all seemed normal. Decorated Army Special Forces Master Sgt. Matthew Livelsberger had an 8-month-old daughter at home and a new assignment involving drones that friends said excited him. He wrote glowing Yelp reviews praising the tattoo parlor in his Colorado Springs hometown and touting the benefits of float spas. And when his father last spoke with him on Christmas Day, he told CBS News, all seemed normal. He "loved the Army and loved America," Roger Livelsberger said. Matthew Livelsberger, 37, was on holiday leave from his station in Germany and his father had figured he would be returning to Germany. He said nothing with his son seemed amiss. Days later, though, Matthew Livelsberger would rent a Tesla Cybertruck, purchase two firearms, take a meandering 1,000-mile drive from Denver to Las Vegas, and place himself at the center of one of two concussive New Year's Day attacks. What led him there remains, at least for now, a frustrating mystery to those who knew him, and to those investigating the attack. "Obviously, we're always concerned in these sorts of events to ascertain what the motive is," said Spencer Evans, Special Agent in Charge of the FBI's Las Vegas Division. "We understand that's at the forefront of everyone's thoughts, and so looking into exactly what the motivation is remains our number one priority." Figuring out what drove Livelsberger to explode a ragtag cache of fireworks and fuel tanks in front of the Trump Hotel on the Las Vegas Strip is not only a priority for law enforcement. It is also a question that has left his family and friends with heavy hearts and a yearning for answers.