If I hadn't been reading both of these at the same time, I would have never made this connection, but, the plot for both of these have basically the same premise, just explored differently. Though the means and reasons are different, both are attempting to escape the death penalty and figure out the truth behind their crimes.
In both of these series there are groups of people who run around trying to rip the clothes off of women in order to see if they have a special mark somewhere on their bodies. In Ageha o Ou Monotachi they are looking for one specific woman, while in Elf wo Karu Monotachi they are collecting numerous markings. These feel like they are both part of the same series, but in reality it's just that they are by the same mangaka.