When a gunman opened fire with an AR-15 at a large high school in south Florida, the 17 dead included students and school workers, young and old. Here is a look at some of some of those who lost their lives in the massacre at Marjory Stoneman Douglas High School:
COACH AND SECURITY MONITOR
The high school football program tweeted that assistant coach Aaron Feis died while selflessly shielding students. The tweet ended: "He died a hero and he will forever be in our hearts and memories."
Feis graduated from the school in 1999 and worked mainly with the junior varsity, the team website said. It said he lived in nearby Coral Springs with his wife and daughter.
At a Thursday news conference, Broward County Sheriff Scott Israel said his two sons played for Feis.
"When Aaron Feis died, when he was killed tragically, he did it protecting others because that is who Aaron Feis was," the sheriff said.
The team website said Feis spent his entire coaching career at Marjory Stoneman after playing there as a student.
The Sun Sentinel reported that Feis, acting as a school security guard, responded to the original call on a school walkie-talkie. Someone on the radio asked if loud sounds they heard were firecrackers, said football coach Willis May, who also carries a radio.
"I heard Aaron say, 'No, that is not firecrackers.' That's the last I heard of him," May said.
Feis' online biography at the team website says he played center at the school from 1995-98, and worked with junior varsity and varsity lineman. He also served as the college recruiting coordinator and worked with football operations.
"He was a great guy," sophomore Douglas lineman Gage Gaynor told the newspaper. "Everyone loved him. Shame he had to go like this. Always gave his all to making us better. Definitely learned a lot from him."
ATHLETIC DIRECTOR 'WAS JUST AMAZING'
A married father of two and the athletic director at Marjory Stoneman Douglas High School, Chris Hixon wasn't shy about jumping in wherever he was needed, said friend and one-time colleague Dianne Sanzari.
Hixon was a member of a Roman Catholic church in Hollywood. The Archdiocese of Miami confirmed his death Thursday.
When a volleyball team needed a fill-in coach, Hixon took over; the same thing happened with the wrestling team, Sanzari said. And when the school needed someone to patrol the campus and monitor threats as a security specialist, Hixon did that, too.
"While he was a security monitor, he did the very best he could to also serve in that athletic administration role," said Sanzari.
It was in that security role that Hixon apparently came within range of the shooter. Sanzari, a retired athletic director, said she was stunned when she heard Hixon had been shot, then cried inconsolably when she found he had been killed.
"He loved his family, he loved his job," she said. "Chris was just amazing."
'AN ANGEL TAKEN AWAY FROM US'
Meadow Pollack's parents called her phone repeatedly only to hear it ring, as they kept an anxious vigil outside the hospital. But on Thursday, her father, Andrew Pollack, confirmed that his daughter was among the dead, the Palm Beach Post reported Thursday.
Eighteen-year-old Pollack, a senior, had planned to attend Lynn University, her father, Andrew Pollack, said, showing the newspaper a photo of their daughter wearing a dark strapless dress.
"Her life was taken way too soon and I have no words to describe how this feels," friend Gii Lovito posted on Facebook.
Family friend Adam Schachtel said in a Facebook post that "an angel was taken away from us in that horrific tragedy ... no words can be said so just prayers and sadness."
The Palm Beach Post reported that Pollack's parents had gone to the hospital to look for their daughter after she didn't answer repeated phone calls.
VICTIM'S FAMILY: "LIVE FOR ALYSSA!"
An amateur soccer club said one of its players, Alyssa Alhadeef, was among the students killed in the mass shooting at Marjory Stoneman Douglas High School.
Parkland Soccer Club posted on its Facebook page that Alhadeff was a "loved and well respected member of our club and community."
The club posted a note it said was from her family which read: "To Alyssa's Friends honor Alyssa by doing something fabulous in your life. Don't ever give up and inspire for greatness. Live for Alyssa! Be her voice and breathe for her. Alyssa loved you all forever!"
The organization asked members to wear red uniform tops and meet at a soccer field for an event to honor Alyssa.
"Feel free to bring flowers and candles," said the note.
Fourteen-year-old Alaina Petty was among those who died in the shooting, great-aunt Claudette McMahon Joshi confirmed in a Facebook post.
"There are no hastags for moments like this, only sadness," she wrote, asking people to lift up Petty's family in prayer.
Petty attended a local Church of Jesus Christ of Latter-day Saints. Petty was a "valiant young member of the Coral Springs Ward," Church leader Stephen E. Thompson wrote in an update.
GEOGRAPHY TEACHER HELPED STUDENTS
Students said geography teacher Scott Beigel, 35, helped them enter a locked classroom to avoid the gunman and paying for the brave act with his life.
"If the shooter would have come into the room, I probably wouldn't be speaking to you now," student Kelsey Friend told Good Morning America.
Friend said when she heard gunshots and realized it wasn't a drill she followed other students toward the classroom.
Beigel "unlocked the door and let us in," she said. "I thought he was behind me, but he wasn't. When he opened the door he had to relock it so we could stay safe, but he didn't get a chance to."
Student Bruna Oliveda said she saw Beigel blocking the door.
"I don't know how we're alive," she said.
Facebook friends remembered Beigel as "an inspiration to many" and "my hero."
Reeves reported from Birmingham, Alabama. Contributing to this report was Tammy Webber in Chicago; Rebecca Boone in Boise, Idaho; and David Porter in New York.