I did a short look into this and haven't found anything that I am willing to attest to the fact. I did find out the following that might be a clue or something that you can connect with your question:
Warwickshire is located within the City of Hamilton
2 Union camps were located in the general area that possibly could have held Confederate POWs: Camp Hamilton in Butler County and Camp Dennison in Hamilton Co.
It was interesting that 31 Confederate soldiers who died at Camp Dennison were buried in the Waldschmidt Cemetery (re-interred to Spring Grove Cem or at Camp Chase).
Also interesting was that this is the same area where Gen. John Morgan made his famous Ohio raid.