The Grexa sisters were raised on Summerdale Avenue in unincorporated Norwood Park Township, next to notorious serial killer John Wayne Gacy.

What was it like growing up next to Gacy? And what can we learn from the prison letters he sent the Grexas’ mother? Larry Potash has the Backstory.

Backstory with Larry Potash airs Saturday nights at 6 p.m. on WGN. Catch up on previous seasons of Backstory with the podcast at WGNtv.com/Backstory via Stitcher, iTunes, Google Play, or wherever you get your podcasts.