The Polk County Sheriff's Office, the State Fire Marshal, and the Hillsborough Sheriff's Office Bomb Squad have joined the investigation, the Ledger reports.
No one was injured by the explosions, which occurred at about 5:30 p.m.in an unpopulated service corridor at Eagle Ridge Mall, which is about 30 miles east of Tampa, Florida, according to NBC News.
While en route, responding crews learned part of the mall was on fire.
When the arrived, the fire department said they saw smoke coming from a hallway next to the mall entrance of JCPenny.
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Lakes Wales Deputy Police Chief Troy Schulze, whose son was working at the mall at the time, said families had been shopping when they heard a "boom".
Even as the police was investigating the explosion, another suspicious package was recovered near the movie theatre.
No injuries were reported, the police said.
The mall was evacuated as a precaution. They also located a backpack in the same corridor with other possible improvised explosive devices in it.
He was last seen wearing a gray-colored shirt and hat.