Is there anyway to release arrested prisoners like Alphonso DiCerbio, Ethien de pasque after I put them in cage? or we have no choices but to burn them or caged them there forever?

I tortured Alphonso and he told the location of the Devil's carven so I don't need him anymore but i just don't want to burn people just for asking a location.

And Ethien de pasque, he's a faithful paladin, maybe he's still redeemable.

I know they did crimes but the purpose for arresting them is for asking a location/evidence of another case at the first place so I don't want to just burn them to dead, and what if I wrongly arrest an innocent person like Edmond d'Arvias, there won't be anyway to get them out?

If I'm not mistaken there is no way to let them go and you have to either burn them or let them rot in prison. If you arrest someone innocent you are able to ask local sheriff to let them go.