It was around dismissal time on a routine school day at Marjory Stoneman Douglas High School when the horror began.

A 19-year-old gunman walked onto the campus of the school in Parkland, Florida, armed with what police say was a military-style semi-automatic rifle and countless magazines, and killed at least 17 people.

It was the latest mass shooting in the United States, and shows that the gun violence epidemic can strike anywhere: Last year, Parkland, a Fort Lauderdale suburb, was named the safest city in Florida by The National Council for Home Safety and Security, a trade association.

The suspect, Nikolas Cruz, 19, is in custody and is being held without bond. He has been charged with 17 counts of premeditated murder, and has not yet entered a plea. He is a former student of the school who got expelled for disciplinary reasons, authorities have said.

Here are names, photos and tributes to those killed in a horrific mass shooting. This list will be updated as victims’ names are confirmed.

Luke Hoyer, 15

15-year-old Luke Hoyer will be remembered as a “happy-go-lucky” teenager who loved basketball and most of all, his two older siblings and parents, his aunt tells PEOPLE.

“He was really laid back,” aunt Joan Cox, who saw him over Christmas in South Carolina, says. “He didn’t get upset. He was always smiling, was so sweet and such a good boy.”

His mother, Gena Hoyer, is in disbelief that the last time she’d ever see her son was when she dropped off him at school on Wednesday, according to Cox.

“We’re all just devastated,” says Cox. “We loved him so much.”

Aaron Feis, 37

Beloved assistant football coach and security guard Aaron Feis died after he jumped in front of the gunman to save the lives of the students he vowed to protect.

Married with a young daughter he adored, the 37-year-old security guard and assistant football coach lost his life “while trying to take the weapon from the shooter,” his cousin, Lori Carter, tells PEOPLE.

Calling Feis a “big ol’ teddy bear,” head football coach Willis May told the Orlando Sentinel, “I trusted him. He had my back. He worked hard. Just a good man.”

Popular with students and colleagues alike, “He touched so many lives,” says Carter.