Olympic champion swimmer Michael Phelps and his wife, Nicole, awoke Monday morning to frightened text messages, asking if they had been at the concert in Las Vegas in which at least 58 people were killed and more than 500 were injured in what is being called the deadliest shooting in U.S. history.

The news from the Phelps household is that, although the couple had been in Las Vegas on Friday night for the Route 91 Harvest show featuring Eric Church and others, they were back home in Arizona when the shooting occurred Sunday night.

“I woke to texts from friends asking if we were still in Vegas, thankfully we were home safe however my heart is heavy this morning after learning of the tragic incident that happened last night,” she wrote on Instagram. “I’m sending love, thoughts and prayers to anyone affected by the shootings ❤️ #prayforlasvegas”

Nicole Phelps, who is expecting the couple’s second child, had shared a photo from Friday night’s show on Instagram, writing, “Perfect #datenight surrounded by good friends to watch an amazing show as always #ericchurch #rt91harvest”

The concerts were part of the Route 91 Harvest Festival that has been held for the past four years on a 15-acre lot across an intersection from the Mandalay Bay Hotel and Casino. The concert’s main stage is situated near the northeastern side of the gold-colored casino and high-rise hotel complex, which towers more than 400 feet above the Strip.

For the son of a Hall of Fame pitcher, the scene at the show was terrifying. Todd Blyleven, a former minor league baseball player, had driven from Dallas and was attending the concert with about 15 friends and family members. They were toward the back of the crowd, center stage when they heard gunfire during Jason Aldean’s second song.

“You look up and you could see the muzzle flashes from the window at the Mandalay Bay,” Blyleven told The Washington Post’s Wesley Lowery. “The stage went black, Jason Aldean and his crew all ducked and ran off stage. Everybody started screaming and then you start to see people going down.”

Blyleven said he and his brother-in-law guided their group out of the venue, ducking behind barbecue vendors’ carts, as shots struck around them. Once he’d gotten his group out, Blyleven headed back into the concert venue, joining a group of volunteers who hoped to get more people out.

“The shooting just seemed like it went on for 10 or 15 minutes,” said Blyleven, who said he saw a police officer who had been shot through the neck and carried out the lifeless body of a young woman. “Young girls and guys, older folks. Just people walking out of a country concert with bullet holes,” he recalled. “Everybody was just trying to do whatever they could to get these poor people out of the gun fire.”

Blyleven said he has no formal medical training felt obligated to do whatever he could to save lives.

“I just felt like I had to,” said Blyleven, who estimated that he may have helped about 30 or 40 people get away from the gunfire. “I would hope that if me, or my family, was in a situation like that, that someone would come in and get me.”

Washington Nationals rightfielder Bryce Harper, who is from Las Vegas, tweeted his love for his hometown. “The pride of Vegas runs deep when you are born and raised in such a great town. I can’t fathom the horrific event that has taken place! My thoughts and prayers go out to the families that have been affected by this and to all the people that have lost their lives way too soon! Las Vegas, I love you and stand with you.”

His brother, Bryan, is a pitcher in the Nationals organization and added that he would be donating blood later today.

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