Here's the deal ... cops say 23-year-old Elijah Samuel Morris is the burglary suspect they've been searching for since January, when he allegedly broke into a vehicle and burglarized a home --- all while wearing a blue dinosaur onesie -- and police say he was arrested Wednesday on separate charges.

Cops say they responded Wednesday morning to reports of vehicle burglaries in progress, and officers saw Morris in a car with 2, count 'em, 2 flat tires. Police say when they hit the sirens, Morris put the car in reverse and drove off before stopping in a parking lot and fleeing on foot.

Police say they tracked Morris down and saw him try to get into another vehicle ... and cops allege he was in possession of a gun that had been reported stolen in Louisville when they made the arrest.

And, get this ... cops say arson investigators from the Nashville Fire Department also identified Morris as the suspect who they believe started a fire outside a home back in December, and now he's facing charges of aggravated arson.

Police say Morris is also charged with aggravated assault, theft of property, theft of a firearm, evading arrest, felony probation violation, possessing a firearm during the commission of a felony and felon in possession of a gun.