Roybal was a Navy veteran and served in the Afghanistan War. He was described as jovial and fun-loving, despite experiencing intense combat during four tours in the Middle East.
His profile page on Facebook said he was from California. However, he was currently living in Denver.
His girlfriend, Maree Elmore, told Denver7 Roybal moved to the Denver area in February. He was working at Crunch Fitness in Colorado Springs but was recently transferred to the gym's location in Aurora.
David Harman founded the company that owns the gym where Roybal worked. He says Roybal was coping with the loss of a friend who was killed by an improvised explosive device. Roybal adopted his friend's bomb-sniffing dog but was devastated when she died.
His co-workers at Crunch Fitness described Roybal as someone who always had a positive attitude, despite the trauma he experienced in Afghanistan.
"He would take a bad mood you had, and you would just laugh all day," said co-worker A.J. Morton. "We worked hard, but we always joke, and that's all I can think about right now, is the why and all the joking."
Roybal was in Las Vegas celebrating his upcoming birthday at the time of the shooting. Elmore recalled the last time she spoke with Roybal.
"He hadn't gone down to the concert yet. We just said 'hi' and 'miss you,' and he had even expressed that he was done with Vegas and that he was ready to come home,” explained Elmore. “He had even joked that he was just going to change his flight so he could head home early, but he wanted to see Jake Owen. He was so excited to see Jake Owen."
After the first text conversation, she texted him again around 9:30 p.m. but got no response.
"I ended up falling asleep, but I left my ringer on because I knew for sure he would call me as soon as he got back to the hotel. But I never ended up getting that call," she said. "I woke up at 4 a.m. to my phone just exploding with all the news about everything that had happened, and I had no texts from him or missed calls, so I started calling his phone, and it went straight to his voicemail."
Elmore said the 28-year-old man was with his mother, Debby Allen, at the concert, but Allen managed to escape the carnage without injury.
Allen spoke to Denver7 sister station KTNV earlier today. Watch the video below:
Several of his friends took to Facebook to honor Roybal. Alexandria Erkelens wrote the two had the "best and weirdest times of our lives."
Matthew Austin, a friend of Roybal, wrote in public Facebook post that the two joined the Navy together when they were "just boys."
In his last public post on Facebook, Roybal wrote about his account in Afghanistan in a post titled "What's it like being shot at?"