I invested in a start up company as an angel investor. I would like to know who the other angels that invested in the company are. Can I do that?
Here are 3 ways you could find out who the investors are.
At any AGM (annual general meeting, which you would have a right to attend) this would obviously be disclosed. Also in the shareholders agreement, all parties would likely sign and you could find out then, and without making a stink.
It depends on the jurisdiction but you could be able to see the public filings. This can be bad because generally it's not advantageous to have your ownership as public knowledge.
Why not just ask the entrepreneurs for an intro? You gave them money, surely they could introduce you to other investors...