The phrase "former inmates" refers to people who were previously in prison or jail but are now out and no longer serving their sentence. Full definition
Over the next few decades, the building transformed into a prison and, according to several former inmates, a torture chamber for political prisoners. (businessinsider.com)
Often, former inmates end up back behind bars. (npr.org)
The paper says onerous fees and overly burdensome rules can backfire and make it harder for former inmates to re-enter society. (wbng.com)