Witnesses reportedly told officers that they saw the suspect, later identified as Ralph Shaw of Indianapolis, arguing with the victim.
Shaw is accused of pouring gasoline on the victim and setting him on fire. The victim, who was not named, was transported to Indiana University Health Methodist Hospital via a medical transport helicopter.
Shaw was taken into custody without incident Monday afternoon when he was found at Donner Park. He was booked into Bartholomew County Jail on charges of aggravated battery and two outstanding Marion County arrest warrants.