Crews responded to the scene, an apartment complex in the 2400 block of Rucker Avenue, at about 12:30 p.m. after receiving reports of smoke and flames at an apartment unit there, said Eric Hicks of the Everett Fire Department.
Some witnesses also said they could explosions or booms as the fire spread.
When firefighters arrived they found one person dead inside the apartment unit. The body was removed, but Hicks said he did not yet know the gender or age of the person.
No one else was believed to be in the apartment.
Crews were continuing to extinguish hot spots at the building as of 1:30 p.m.
Hicks said an investigation will determine the cause of the fire, the victim's cause of death and will try to determine whether there were any explosions when the fire started.