mike nelson lived across the street from the building and at age 11 started the one your work and odd for neighbors. but no job was more odd than the jobs he did for gacy. the window to gauge his workshop was painted black. he says that gacy drug strange trenches and a hole in the parking lot to repave it. >> they were black topping a gravel driveway so why did they did so far down? who was i to question. there was some strange oddities that went on and there was something that would be hidden. >> in 1998 chicago police department return to the building and used ground penetrating radar to penetrate beneath the sole soil. the radar company sent a letter saying why did the police only did to calls when the radar company said it found as many as 17 targets. the man who lived across from the building was up late at night with a sick child. he said he would seek gacy out to begin in the dark. >> i would see him out in the molybdenite been digging. i saw bags. i thought maybe there were bag of cement. i don't know what they were. there was never any real meaning you know why he was joined.