15-year old Bart Palosz, who was just entering his sophomore year, fatally shot himself in his house on High Street after the first day of school.
Authorities say their preliminary investigation has revealed that the gun was family owned and had been stored within a gun locker inside the home.
School crisis teams have been convened at the high school, Western Middle School and New Lebanon School, the schools that Palosz attended, and mental health personnel are providing grief counseling to anyone in need.
School officials are also speaking to the young victim's sister, a recent high school graduate.
"No words can express the pain that the family and the community feels," said Greenwich First Selectman Peter Tesei.
One neighbor said the teen had been bullied at the high school.
School officials hope to learn more talking to classmates.
"For whatever reason Bart made the decision he did yesterday, he made a decision. We do not want to have any of our other children make that decision," said Superintendent of Schools Dr. William McKersie.
Asked if they were discussing possible bullyng, the superintendent would only say, "I can't comment on that, other than we are taking everything very, very seriously."
In a statement, the Greenwich school district said: "We take seriously the importance of a positive school climate and the safety and well-being of our students and staff. Any indications that a student is experiencing significant mental health distress is addressed at the school level by personnel trained to recognize and respond to these concerns. Importantly, if any staff member believes that a student poses a danger to him/herself, or others, parents are notified and the student is immediately referred to outside supports and providers."
Other students and some recent graduates wondered about pressure from other students.
"It's a big issue, a kid feels that bad that they don't want to think or live or anything," said recent graduate Jenna Angilello.
And while Bart appears to have been active on social media sites, some wonder if signs might have been missed.
"Teachers and adults aren't used to those kinds of things, so it's hard for them to take notice of that kind of stuff," said recent graduate Andrew Merz.