Got a source on this? Quick google search for "Chicago death iPhone mugging" did not turn up anything about robbers specifically asking for PIN codes, or killing someone for not providing it.
Dakota Earley age 23 was viciously attacked and shot 3 times and barely survived. all caught on video and you can hear the thieves demanding the passcode.
and before you dismiss it given the time of day or one off, armed robberies for cell phones are way up in chicago and they are occurring in broad daylight . the crime that keeps getting covered and that I know someone who this happened to is, 1 -2 people walking on the street, a car pulls up with 4 people . they all get out and have guns and force you to give up your phone and passcode. Armed Robberies are way up 44% 7978 cases and they are all for iPhones and passcodes . people are getting pistol whipped when they don't cooperate and increasingly even when they do.