Frank:

Get a copy of George Levy's book "To Die in Chicago". It is well worth the read given your interest in Camp Douglas.

The prisoners being guarded from September 1862 to November 1862 were the paroled Union prisoners returned under the Dix-Hill Cartel. Camp Douglas was then serving as a parole camp. Thereafter, Camp Douglas was returned to its original use as a recruiting depot and training center. I believe these recruits are the unarmed soldiers being discussed in the January 1863 correspondence.

Hugh