The fire spread from a trailer to a building and five other trucks and trailers at the facility in a Lakewood industrial park late Wednesday afternoon.
Ocean County Prosecutor Bradley Billhimer said the death of the individual found inside the house on Thornbury Court in Leisure Village by Lakewood police is considered suspicious.
The weight loss company Jenny Craig is going out of business after 30 years, and has permanently closed its 16 New Jersey centers, three of which are in South Jersey.
Lakewood police Capt. Greg Staffordsmith said 22-year-old Max Sanchez didn't make a specific threat but his "menacing behavior" caused the individuals to be concerned for their safety.
Authorities say a 24-year-old man has been charged with kidnapping, endangering the welfare of a child, and robbery in connection to a series of events in Jackson Township.