I'm with you. I personally believe the tunnels have something to do with this event. I have a theory (not based on much) that the tunnels secretly reach all the way up to SHE. I think that some of the children were taken into the tunnels.
I've visited Fairfield Hills many times, and it's interesting that recently they are doing a ton of renovating and putting many of their town buildings on the property. I also think its interesting that the tunnels at Fairfield Hills were sealed in 2009.
There is also Garner Prison which is directly behind Fairfield Hills and Helen Joy Previdi & Stephen Sedensky are both are the board there. I bet the tunnels lead through that property too.
I tried to find maps of them, but was unsuccessful.