Derrick Harvey, 19, came into contact with a transformer sometime before 2:45 a.m. Thursday in the 1800 block of West Montrose Avenue, officials said.
Officers found Harvey unconscious, who may have been tagging on the roof before he was electrocuted, police said.
Harvey has a history of tagging arrests, and graffiti was found on the transformer, police said.
Harvey, who lived in the 6600 block of South Stewart Avenue, was pronounced dead at 3:56 a.m. at Advocate Illinois Masonic Medical Center, according to the medical examiner's office.
An autopsy ruled Harvey's cause of death as accidental electrocution.