It seems this manga trying not to stick to the first premise of "punishing" the bad people, the manga trying to explore different type and scenario that Spica will face instead. Like this old Gorou, it's the first time Spica unable to determine someone's past after touching them due to how messy his mind are so it also possible she will have a hard time to dig into Gorou's past murder, let alone dealing with a murderer that already became a different person.
I think it will be interesting doing this way, if the manga always doing the "punish" type of story then it may get boring soon.