We can take neither the killer's life nor his liberty under the circumstances. As far as we know, we cannot simply seal his Persona either. Taking mere property would be too lenient a punishment for his crimes. However, if we could just overcome the obstacle of not knowing how to make electronic devices work during the Dark Hour, there is one thing we may be able to take from him: his privacy.

[Edgeworth turns to Pess and begins massaging her shoulders at that, which she seems to enjoy.]

It's common practice in this era to surgically implant pets with microchips -- tiny devices -- that when scanned with the proper device reveal information about the dog in case they're lost. There are also various tracking devices that can be planted on an object or person -- Franziska once hid such a thing in a certain detective's coat in order to keep him on a leash. Furthermore, our phones are particularly advanced, and should be programmable.

My idea, therefore, is simply this: implant a miniature tracking device inside our killer's body, and distribute to everyone the program necessary to detect it. In such a way, it would be substantially more difficult for the killer to take new victims unawares or to escape further justice. The problem lies in the fact that unless we unravel the mystery of how our phones work during the Dark Hour, the device would be inactive during that time.