Syracuse, N.Y. -- Brian Deforge had worked as a janitor at the Syracuse Academy of Science charter school for a little over three years.
He made sure to share a laugh or talk to any students or staff he saw during his evenings at the school, said his sister Kathryn Duvergel.
He loved his job, she said.
Deforge went to work as usual Monday but was found dead Tuesday morning in the cafeteria.
His family believes the 46-year-old Syracuse man died from carbon monoxide poisoning.
Firefighters were called to the school at 1001 Park Ave. Tuesday morning when school staff found Deforge. A carbon monoxide detector on the firefighters' equipment went off indicating high levels of the carbon monoxide.
Twelve adults were evaluated and five were transported to hospitals with symptoms consistent with mild to moderate exposure to carbon monoxide.
On Wednesday, Bekir Duz, the charter school's assistant superintendent told Syracuse.com | The Post-Standard the death appeared unrelated to the deadly gas. School officials said video in the school shows he was dead before a food warmer - said to be the source of the carbon monoxide - was turned on.
Syracuse police are investigating his death. No official cause of death has been made public.
At a vigil held outside the school Thursday afternoon, his family said his death could have been prevented.
"We're devastated he lost his life because of neglect on the school's part and the fire department's part," Duvergel said.
Syracuse.com reported Thursday that in November the Syracuse fire marshal gave the school passing marks during an annual safety inspection including having proper carbon monoxide detectors. After the high levels of carbon monoxide were detected Tuesday, it was discovered what was thought to be a smoke and carbon monoxide detector only detected smoke.
Duvergel said the family is also frustrated they haven't been contacted by the school. They were informed Deforge had passed away due to her cousin having children at the school, she said.
"She was here picking up her children because the school was being evacuated and she found out it was her cousin, my brother," Duvergel said.
On Thursday, a crowd of about 20 had gathered outside the school for the vigil in the snow and cold. Some would light candles or add a balloon or picture of Deforge to the chain-linked fence next to the front entrance.
When Deforge wasn't working, he liked spending time with his two cats and friends, Duvergel said through tears.
Every Sunday he would go sit with a friend outside of Assumption Church at 812 N Salina St., his sister said. He would get food from the church, sit and talk with a friend and sometimes feed the birds outside.
The family has started planning a funeral for Deforge, but due to his sudden death they have created a GoFundMe to help cover funeral costs.
To Duvergel, her brother died as a hero. If he wasn't found that morning, she said many would've gone on with their day without realizing something was wrong. But she said how he passed, is painful to accept.
"He was all alone," she said.