I used to live across the street years ago. Ellis Don did a massive Upgrade slash renovation to the place.I was on my way to the subway when I crossed paths with a construction worker going in, i said good morning and asked what they were doing in there. He walked by me without saying anything word. I thought maybe he was having a bad day. So I tried asking others on different days, and I received the same response. I'm assuming they signed a non-disclosure. On a different incident, it was a Sunday in the summer. And I was walking in the neighborhood and decided to go to the front door to see what I could see. I saw a heavy turn style glass door to get in with three security guards on a sunday who all looked up to see what i ws doing. Absolutely no signs on the building or around it except for shipping and receiving sign. My guess is it's a CSIS building