I can’t recall all the investigations Horowitz mentioned at the house and senate IG hearings that were ongoing and he wouldn’t comment on. But I remember hearing; Comey leaking his memos. FBI agents taking graft for leaking. Fisa abuses. Hillary server/emails. Clinton foundation. He did not go into details but mentioned each and there were at least 5 IIRC
I thought he said 3. But I had the impression there were a LOT more. I thought he was being a bit cagey, playing it close to the vest.
If I knew that my questioners/listeners knew that there were X investigations, I would pick a number near X to acknowledge, even if there were 100X. Or especially if there were 100X.