Police said officers were taking a man in his 30s into custody for allegedly shoplifting at the North Side retailer just after midnight Wednesday.
Witnesses said the man was resisting arrest, which prompted a uniformed officer to ask the man whether he wanted the officer to use his stun gun. Witnesses said the man broke free and started running.
Police said the officer used his stun gun moments after, prompting the man to immediately stiffen and fall into a light pole near North and North Park avenues. The man then fell to the ground and appeared to be unresponsive.
"I'm still trying to put the pieces of the puzzle together myself," a witness said. "All I know is there was a man not moving in the street. There was just a lot of cops. The ambulance took him away and that was basically it."
The suspect is being treated at Northwestern Memorial Hospital.