It could be anyone, that’s how FiveEyes works. Your allies spy on you, and give you the intel in a completely deniable way. Technically, you weren’t spying on India; technically, you weren’t spying on Canadian citizens; technically, you weren’t spying on diplomats. It could have been New Zealand, it could have been the US, and that’s very naughty of whoever it was, but you’ll never know who.