A 16-year-old boy was killed and a man wounded in an exchange of gunfire after police say the teen attempted to rob another during a meet-up for a sale arranged online Wednesday in suburban Cicero.The incident unfolded around 3:20 p.m. when two teens met in the 1300 block of South 58th Avenue for th e transaction that was arranged via social media, Cicero police said. A man related to the teen selling the item waited nearby in a car.The sale fell through and as the seller walked away a third teen approached him and tried to steal the item, according to police. The two struggled over it and when the seller's relative got out of the car the teen who tried to take the item shot the man twice.But the relative returned fire, striking the robber once, police said.The teen believed to be the robber later showed up with a gunshot wound at Rush Oak Park Hospital, where he died, police said.He was identified as Angel Dominguez, 16, by the Cook County medical examiner's office. An autopsy found he died of multiple gunshot wounds.The seller's relative was taken to Loyola University Medical Center in Maywood, where his condition was stabilized, police said. Authorities said Thursday that the man remains hospitalized.The teen buyer in the transaction has been charged as a juvenile with armed robbery after an investigation found the theft was a plan "developed between him and the deceased," according to police.An investigation is ongoing, and police reminded residents that police stations are safe places to conduct online marketplace transactions. ...read more read less