An active-duty U.S. soldier who was in a Tesla Cybertruck that exploded Wednesday outside President-elect Donald Trump’s Las Vegas hotel had rented the vehicle five days earlier in Denver, authorities said.

The 24-year-old said his older brother had increasingly isolated himself from family and friends in the last few years but he hadn’t seen any signs of radicalization when they talked. He said it had been a few months since he had seen his brother in-person and a few weeks since they talked on the phone.