Send Them Away. I thought it was interesting that people with different professional backgrounds and levels of experience pretty much agreed on what to do, who to keep and who to send out.
Since people seemed to enjoy speculating on the back stories, I thought I'd supply the endings.
Patient A was kept in the jail and admitted to the infirmary. After a few days of medication he quickly got better and was able to tell you what happened since his last release. His mother tried to get him an appointment at the local mental health clinic shortly after he got home, but she was told there was a three month wait until the first available appointment and that she should call the police or take him to an emergency room if it was an emergency. After he ran out of his thirty day supply of release medication he went to the emergency room to get it renewed, but when he ran out of meds a second time he was told he could no longer get his meds renewed through the emergency room. It didn't really matter though since his benefits were cut off while he was in jail and he couldn't afford them anymore anyway.
His mental state went downhill quickly after that. His mother, the much-beloved Cookie Lady (as she was known in the neighborhood), didn't stand much of a chance. I'll spare you the details. As a well-trained forensic psychiatrist you know that ethical standards for correctional work forbid you from collecting forensic evidence in jail as a treating clinician, so you are circumspect about your documentation as it regards the current offense. Eventually, an outside forensic evaluation is done and Patient A becomes an insanity acquittee. He is transferred to a forensic hospital.
Immediately after the verdict, there is public uproar. The local newspaper publishes an opinion piece calling for reform of the public mental health system and looser standards for civil commitment and involuntary treatment. A state delegate proposes legislation for outpatient civil commitment. The governor organizes a task force to study the issue and the entire police force is required to undergo crisis intervention and mental health training. Mental health advocates decry Patient A's incarceration, loudly insist that jail couldn't help anybody, and accuse the jail (not you in particular, but the jail) of giving lousy, horrible, inadequate or nonexistent care. (Meanwhile, the somatic jail doc has diagnosed Patient A's new-onset diabetes and Patient A is getting a diagnostic workup for the lump that was discovered on his admission physical---it turned out to be benign. Because of patient confidentiality, none of this can be revealed to the public but you know it.) Meanwhile, on the newspaper internet discussion board some people express outrage that "that dangerous nut case" should have been sent to prison forever, given the electric chair, or made to undergo the same horrible acts he did to his mother. Patient A reads all about this in the newspaper delivered to his ward, and hears about it on the ward television news reports.
Years later, many years later, Patient A is quietly granted conditional release by a sympathetic judge, with the support of the local state's attorney. He goes to live back in his old neighborhood---now gentrified beyond recognition, where he spends a few minutes every morning sipping coffee at the corner Starbucks. His neighbors---a young attorney fresh out of law school, a music student at the local conservatory, and a young couple who work for the local newspaper, see him there and exchange casual greetings. They think he is a shy but likable guy, a quiet but kind person. They enjoy having him as a neighbor.