Hollywood loves couples from great comedy duos like Cheech and Chong to buddy cops, Riggs and Murtaugh, in the Lethal Weapon movies. If one killer is good, then two are even better, especially if there is a romantic link. Doubling up on the sociopaths also has the transformative effect of turning them into protagonists.
Source：https://www.cbr.com/killer-couples-romance-crime/
