This thread is the perfect example of the difference in the mentality of Indians and Pakistanis
When Pakistan announced MFN status to India, Most of the Pakistani were against the decision (even if it was helping them economically) or when there was article about India supplying Locomotives to Pakistan then again the reactions were similar (Same Locos in India were working perfectly for decades under similar condition as Pakistan but people were not in favor of deals because they were Indian)
On the contrary here, the Indian members guessing this anonymous investor as India are not criticizing their government's move.
On topic:
The anonymous investor is not a traditional Pakistan ally because then it doesn't make sense to hide identity (so no China, Turkey, KSA and other GCC Nations)
Which left us with the Countries that can get benefits by this pipeline construction. (Possibilities: India {energy supply}, Russia {getting back its hold in south Asia}, US {this investment might be a part of the deal and US doesn't want to jeopardize its relations with GCC countries by revealing its identity})