Shamsud-Din Jabbar grew up in Texas, joined the U.S. Army and eventually settled in Houston, where he spun up a real estate business and made $120,000 a year for one of the world’s largest consulting firms. On Thursday, authorities and relatives were still piecing together why Jabbar barreled through a crowd in a Ford F-150 on Bourbon Street, killing 14 revelers and injuring at least 30 others. Officials said the attack was inspired by the Islamic State group, making it one of the deadliest IS-inspired assaults on U.S. soil in years.