The suspect, identified as a male between the ages of 13 and 15 years old, was arrested shortly after the incident, which was captured on cameras around the apartment complex where both teenagers lived, KXAS reported. Reynolds' death has sparked an outpouring of grief from the community, and authorities have condemned the shooting as "so senseless."
By today, tens of thousands of dollars had been donated to help the Reynolds family and countless tributes remembered the high school sophomore for his "heart of gold."
"He cared about people and he did what he thought was right," Shay Tyes, a family friend, told KXAS.
The deadly confrontation played out outside Pinewoods Apartments, located near the University of Texas at Arlington's main campus.
Reynolds was seen on video walking between two buildings when the teenage suspect approached him, KTVT reported.
"He pulls out a handgun from the rear part of his pants he was wearing, points it at the victim and fires one round," Cook told reporters, according to KXAS.
Police arrived and found Reynolds suffering from a gunshot wound. The 16-year-old was rushed to a nearby hospital where he later died.
Cook said one shell casing was recovered from the scene, adding that authorities believe a .40-calibre semiautomatic handgun was allegedly used. The gun has not been recovered yet, BuzzFeed News reported.
Arlington Police Chief Will Johnson announced that an arrest had been made, tweeting, "We have a lot of work to do on this case tonight." In another tweet, Johnson described the shooting as "emotionally tough" on everyone involved and stressed that the investigation would look into how the young suspect ended up with the weapon.
The alleged shooter has since been moved to a juvenile detention centre and is facing a murder charge, according to KXAS. It is unclear whether he will be tried as a child or an adult.
"This senseless act of gun violence has no place in society and our hometown community," Johnson tweeted.
Cook echoed Johnson's statement during Friday's news conference.
"We are sick and tired of children in our community coming into contact with firearms and possessing them and using them in this type of manner," he said. "If an adult has provided this firearm, you certainly can bet that we're going to pursue them vigorously."
Meanwhile, Reynolds's family, friends and community are struggling to cope with the sudden loss.
"My partner in crime," wrote Reynolds's mother, Madison Fletcher, in a recent Facebook post. "He was the definition of silly. My sweet, sweet boy."
Arlington High School principal Shahveer Dhalla wrote, "We are heartbroken."
"He touched the lives of many of our Arlington students and teachers, and he will be missed," Dhalla wrote of Reynolds. "We are keeping our thoughts and prayers with Sam's family and friends."
A large crowd of mourners gathered in the high school's parking lot for a candlelight vigil. Videos showed many tearfully embracing Fletcher, who encouraged attendees to share their memories of her son. Reynolds was an avid soccer player who was well-liked for "his charming personality and wonderful sense of humour," his family wrote in an obituary. The teenager's funeral is scheduled to take place later this week.
Russell Laniyan remembered Reynolds lending him his soccer cleats when he didn't have any.
"He would do anything to support his friends and anyone he found close to him," Laniyan said, according to WFAA. "I thank him for the impact that he made on my life."
"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," Laniyan added, according to KXAS.
