A serial killer is " a person who commits a series of murders, often with no apparent motive and typically following a characteristic, predictable behavior pattern." If it is a tell-tale sign that something is wrong with them, then I think that the States should reconsider to what point a mentally ill person should get the chair. Look, this is a tricky subject to talk about because we don't know everything yet about the human mind. But maybe there are some exceptions as to when a mentally ill person should get capital punishment. https://deathpenaltyinfo.org/mental-illness-and-death-penalty