As gun shots rang out at a Florida high school on Wednesday, a call on the school's security radio asked if the loud sounds were firecrackers.
Aaron Feis, in his capacity as a school security guard, responded: "No, that is not firecrackers." It was the last anyone heard from him.
It later emerged that as others fled the gunman, Mr Feis had put himself in harm's way, using his own body to shield his students.
"He died the same way he lived - he put himself second," said Denise Lehtio, a spokeswoman for Marjory Stoneman Douglas High School in Parkland, Florida.
"He was a very kind soul, a very nice man. He died a hero."
Mr Feis, who a former student of Marjory Stoneman himself, was also an assistant football coach at the school.
In a statement, the team said: "He was our Assistant Football Coach and security guard.
"He selflessly shielded students from the shooter when he was shot. He will forever be in our hearts and memories."
Mr Feis was one of at least 17 victims in Wednesday's deadly massacre, along with 13 teenagers and two other staff members who were shot and killed by former student Nikolas Cruz.
The massacre has shocked the small, tight knit community of Parkland, Florida.
The middle class town, 50 miles from Miami, was named the Florida's safest town last year with just seven violent crimes recorded.
Scott Beige, a 35-year-old Geography teacher at the school, was also killed as he attempted to save his students' lives.
He was hit by a bullet as he ushered frightened students into his classroom to take shelter.
Scott Beige, 35, was a geography teacher at the school who unlocked his classroom to allow panicked students to take shelter inside during the shooting. He was struck and killed by a bullet while closing the door behind them. pic.twitter.com/yoz6UHbHCZ— Julia Armstrong (@jugiearmstrong) February 15, 2018
Kelsey Friend, one of the students he saved, told CNN: "When he opened the door, he had to re-lock it so that we could stay safe, but he didn't get the chance."
Addressing Mr Beige's family, the teenager said: "Thank you... for giving him the power to be stronger than I could have ever been.
"He will forever be my hero. I am alive today because of him".
Chris Hixon, the school's athletics director and a wrestling coach, was also among the dead.
The 49-year-old married father was described as the kind of person "who would give you the shirt off his back" by a colleague.
Dan Jacob, the athletics director at nearby Coral Springs High School, said: “Chris is probably the nicest guy I have ever met. He would give you the shirt off his back.
"He does so much. That is terrible that it would happen to anybody. It is so senseless. I am totally crushed,” he told local newspaper the Sun-Sentinel.
Jaime Guttenberg's family desperately searched for their teenage daughter when she did not return home along with her brother Jesse, before learning she had been killed.
Her father, Fred Guttenberg, said his heart was "broken" after he and his wife Jennifer learned of the news.
“I am broken as I write this trying to figure out how my family get's through this," he wrote on Facebook. "Hugs to all and hold your children tight.”
Nicholas Dworet, 17, who was soon to take up a swimming scholarship at the University of Indianapolis, waved goodbye to a classmate shortly before he was gunned down.
His classmate, Alex Greenwald, wrote on social media: "We had class together earlier in the day. 'See you tomorrow', you said as you walked out. But I won't see you tomorrow, or next week, or next month.
"We walked into kindergarten together, so knowing you won't be walking across the stage at graduation with me in a few months is devastating and heartbreaking."
Martin Duque, a 14-year-old student, was confirmed to be among the fatalities by his older brother Miguel, who graduated from the school last year. “Words can not describe my pain,” he wrote. “You’ll be missed buddy.”
Gina Montalto, 14, was feared dead when she stopped answering her phone in the aftermath of the shooting.
One of her former sports instructors, Manuel Miranda, described her as "kind, caring, always smiling" as she confirmed the news on Wednesday night.
Alyssa Al Hadeff
Alyssa Al Hadeff, 15, was confirmed dead by her cousin, Ariella Del Quaglio, on Thursday. "Many innocent souls were taken a few short hours ago," she said. "Among them we just got confirmation was my little cousin. My heart is broken. I am at a loss for words".
Luke Hoyer was killed on the third floor of the school, his family members said, paying tribute to their "precious" child.
The 18-year-old had planned to attend Lynn University, the Miami Herald reported.
“Please say a prayer for the family of an amazing girl I got to call my bestfriend growing up,” posted her friend Gii Lovito on Facebook. “Her life was taken way too soon and I have no words to describe how this feels.”
The 14-year-old was confirmed to be among the victims by a peer counselor at her much.
“RIP Cara, and fly with the angels. You will be greatly missed, and we will always love you and celebrate your beautiful life,” her neighbour wrote on Facebook.
Aged 16, the former National Merit Scholar semifinalist was confirmed dead on Thursday morning by several friends on social media.
"Rest In Peace Carmen Schentrup. Your family is forever in my thoughts and prayers. I’m so sorry," tweeted Pranati.
Carmen Schentrup, 16— David Begnaud (@DavidBegnaud) February 16, 2018
“Her cousin, Matt Brandow, called her "the smartest and most intelligible 16-year-old I've ever met.
According to the Broward County Public School system, Schentrup was a 2017 National Merit Scholar semifinalist.” pic.twitter.com/oSW1DWwQQ9
Alaina, aged 14 years old, was also killed, according to friends and family.
In a statement, her family said Alaina was a member of the JROTC programme and volunteered with the “Helping Hands” programme of the Church of Jesus Christ of Latter-day Saints, including a cleanup of the Keys after Hurricane Irma.
“It is impossible to sum up all that Alaina was, and meant, to her family & friends,” the family wrote, according to the Miami Herald. “Alaina was a vibrant and determined young woman, loved by all who knew her.”
This is Alaina Petty. She was just 14 years-old & was tragically killed yesterday in the shooting at Parkland High School. Her Great-Aunt wrote “There are no hashtags for moments like this, only sadness.” Petty was only a freshman in high school.#GunReformNowpic.twitter.com/wAuc1ptfNl— Simar (@sahluwal) February 15, 2018
Joaquin Oliver, 17, was confirmed dead by his girlfriend, Victoria González. He had become a US citizen last year, after moving from Venezuela at the age of three.
The 14-year-old marching band student at the school was confirmed dead by a former instructor as well as by Congregation Beth Am in Longwood.
Peter Wang, 15, was last seen on Wednesday holding a door open so other people could escape, his cousin Aaron Chen said.
Mr Chen later confirmed to local media his cousin was among the fatalities. “He wasn’t supposed to die,” he told First Coast News.
“He was supposed to grow old with me.”
The 17-year-old was due to start college next year.
A family member, in a lengthy Facebook post, called her a “smart, kind hearted and thoughtful person.”
“Though she was some what reserved, she had a relentless motivation towards her academic studies, and her soft warm demeanor brought the best out in all who knew her. She was so brilliant and witty, and I’m still wrestling with the idea that she is actually gone.”
This is Helena Ramsay, she was 17 years-old. She was killed in Florida yesterday. Helena had a “relentless motivation towards her academic studies & her soft warm demeanor brought the best out in all who knew her.” She was going to start college next year.#GunReformNowpic.twitter.com/a5IZgDqU7v— Simar (@sahluwal) February 16, 2018