• Heroes saved countless lives as gunman rained bullets down on concertgoers

LAS VEGAS — Rob Ledbetter’s battlefield instincts kicked in quickly as bullets rained overhead.

The 42-year-old U.S. Army veteran who served as a sniper in Iraq immediately began tending to the wounded, one of several heroes to emerge from the deadliest mass shooting in modern U.S. history.

Amid the massacre in Las Vegas, which left 59 people dead and more than 500 injured, there were acts of compassion and countless heroics that officials say saved many lives throughout the unhindered gunfire that appeared to last for more than 10 minutes.

There was a man one survivor knows only as Zach who herded people to a safe place. There was a registered nurse from Tennessee who died shielding his wife.

Like many people in the crowd of some 22,000 country music fans Sunday night, Mr. Ledbetter heard the poppop-popping noise and figured it was fireworks.

Then he saw people dropping to the ground. When more booms echoed in the night air, he recognized the sound of automatic weapons fire.

“The echo, it sounded like it was coming from everywhere and you didn’t know which way to run,” said Mr. Ledbetter, who was at the concert with seven people including his brother, who was shot and injured, and his wife.

They found cover in a VIP area of the concert. Once out of harm’s way, he turned to injured strangers.

Thanks to a man who took the flannel shirt off his back, Mr. Ledbetter says he put a makeshift tourniquet on a wounded teenage girl.

Mr. Ledbetter said he would have helped more people, but couldn’t clear the barrage of gunfire.