Police say the suspect threw the Molotov cocktail, a flammable liquid inside a glass bottle, through a window at 125 East Hampden Avenue around noon Friday.
The building - which houses a Health One rehabilitation facility - has a full fire sprinkler system which contained the fire. There were no injuries.
Police have not released a motive or the name of the suspect.
Damage to the structure is estimated to be around $15,000.
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