Samuel Reynolds was remembered by his friends as a hero. Photo / Supplied
A 16-year-old boy was shot dead days after he broke up a fight to protect a smaller boy, in a tragedy that has shocked a US school and community.
Samuel Reynolds, a student at Arlington High School in Texas, was shot and killed last Thursday at the apartment where he lived in what local police called a "senseless act".
Days earlier, Reynolds had seen another student getting picked on and intervened to protect him.
"Our victim had broken up a fight a few days prior with a smaller - what he described as a smaller - boy that was being picked on and after he broke up the fight he started having some trouble with the suspect," said Officer Christopher Cook from Arlington Police.
KTVT news reports that police identified a 15-year-old from CCTV footage that showed the younger boy pulling a .40 calibre gun on Reynolds and shooting him.
Reynolds was rushed to a nearby hospital but pronounced dead a short time later.
The 15-year-old, who was still in middle school, was the same boy that Reynolds had stopped from picking on the smaller child, police say.
He lived in the same apartment complex as Reynolds and initially denied involvement, but CCTV captured the entire incident.
"He [suspect] pulls out a handgun from the rear part of his pants he was wearing, points it at the victim and fires one round," Lt Cook told reporters. "We did recover one spent shell casing. It's a .40 caliber semi-automatic handgun."
Arlington Police Chief Will Johnson took to social media, asking how the young teenager had access to the gun: "This senseless act of gun violence has no place in society and our hometown community.
"This was an emotionally tough case for responding officers, investigators and medics. We will direct our attention to how a young teen suspect accessed a firearm used in the offense."
The Arlington High School community is rallying after the tragedy and gathered together last Friday for a vigil on campus.
Principal Shahveer Dhalla said in a statement that the school was "heartbroken by this tragic loss of a young life.
"He touched the lives of many of our Arlington students and teachers, and he will be missed. We are keeping our thoughts and prayers with Sam's family and friends."
Students, teachers, friends and family gathered together this evening to remember Samuel Reynolds in a candlelight vigil...
Friends gathered at the school remembered Reynolds as a giving and caring friend, who once gave another boy the shoes off his feet during a football game, so he could play while Reynolds sat on the bench.
Student Russell Laniyan said: "I think this just encourages us to go out and to be like Sam and to follow the example that Sam has set for us.
"He obviously fought until the end. He cared about people and he did what he thought was right," family friend Shay Tyes told NBC.
The young suspect is being held in juvenile detention and faces a murder charge. It is yet to be decided whether he will be tried as an adult or as a child.