So I did a bit of a dive and this is what I found:

Committee rules may provide for the full committee to issue a subpoena, or permit subcommittees or the chairman (acting alone or with the ranking member) to issue subpoenas..

https://en.m.wikipedia.org/wiki/Contempt_of_Congress

So clarify with a lawyer and ensure that this action was taken under full legal authority and it likely was. I will edit my main comment to prevent the spread of misinformation