Thanks for getting in touch with me.
Unfortunately I wasn't able to find info on why they were incarcerated. I did have a genealogist check the State records, but they weren't in any State records. It's likely it was a local or County "offense" but I haven't been able to check those (I live in Washington State).I sure am curious as to the circumstances.
I believe that this Robert was married to Maggie Kathryn Parish who was a half sister to my grandfather. I have death certificate for Robert and Maggie as well as her obit. Would love to correspond with you re this family. Contact me at my email address firstname.lastname@example.org
I will look forward to hearing from you and sharing info.