An autopsy determined that Samir Anbari, 21, was trapped in the building and died of smoke inhalation early Saturday.
The Hamilton man had been working overnight on renovations to the building, Hamilton police Det. Sgt. Matt Kavanagh told a news conference Tuesday morning.
The fire broke out Saturday morning at 810 Main Street East, at the corner of Ashford Boulevard.
Two vehicles “were loaded with gasoline, brought to the business and set on fire,” Kavanagh said. “That's what started it.”
The building was being converted from a 7-Eleven into a Subway restaurant as well as a Big Bee convenience store.
Sami Karnaz, 30, has been charged with arson and disregard for human life. Police say he will now be charged with second-degree murder. He is scheduled to appear in court Wednesday morning.
Police believe others may have been involved. The motive is unknown.
The owners of the building have owned it for several years and have no connection to the accused, Kavanagh said.
When police arrived at the scene around 4 a.m. Saturday, “the place was totally involved with flames,” said Staff Sgt. Jack Longhorn.
Police are continuing to investigate.