Transcript for Las Vegas shooter booked hotel overlooking Lollapalooza, seen with mystery woman
Investigators now delving into the elaborate planning on Sunday night's attack on this country music festival in Las Vegas. Now think it's possible gunman Stephen panicked parents some type of hell. This troublesome that this individual. Was able to move this amount of gear into a hotel room on assisted. An official briefed on the investigation says pat Christine with a woman in his final days they're now trying to figure out who she is as the FBI questioned his girlfriend Mary Lou damn late now a person of interest her attorney reading a statement she wrote denying any knowledge. He never said anything Twomey or took any action. That I was aware of that I understood it any way to be a warning. That something horrible like this was going to happen. Investigators are now looking into the possibility panic may have planned to attack earlier sources saying patted booked hotel rooms in Chicago in August during the -- pollute the festival authorities also say he rented a room at this Las Vegas Condo overlooking a different concert just a week before the massacre that left 58 innocent people dead 487. Others injured among them he's used compost the security guard the first to approach addicts hotel room the gunman shooting him through the door. This bravery was amazing because. He remained. With our officers provided in the KeePass. Excessive gore and actually continued to help him clear rooms until or officer demanded that he go seek medical attention. Have a sub ABC news he was just doing his job and that he's doing okay but today more than a 150. Others injured in the attack are still hospitalized. RC Gonzales ABC news Los Vegas.
This transcript has been automatically generated and may not be 100% accurate.