In act one of Shakespeare's Macbeth, the idea that guilt shows on a person's face is a motif that runs throughout the play. Lady Macbeth warns her husband early on "Your face, my thane, is as a book, where men may read strange matters." She advises him to "...look like the innocent flower, but be the serpent under't."
Macbeth has a conscience - Lady Macbeth doesn't. By the end of act one, he tries to take her advice, "False face must hide what the false heart doth know." A person with a conscience cannot pull that off - unfortunately, a sociopath can. By the end of the play, King Macbeth has become a serial killer, through his henchmen, of men, women, and children.
Broca believed in the concept of the born criminal who was a "throwback to earlier hedonistic races." In the twentieth century, this theory was strongly reinforced in the popular culture through movies, dime novels, pulp fiction, radio mystery shows, and television crime dramas. Rather than scientific, these ideas broke along racial, ethnic, and religious lines more often than not. The Nazis made great use of this junk science which they proudly documented in the last century.
Today, crime science has reliable and irrefutable tools like fingerprints, DNA analysis, and chemical and fiber labs to help catch and convict sociopathic killers. The trouble is that someone must lose their life before any of this science can be put to work.
Understanding "the construction of the mind" simply by looking at someones physical traits does not work. Sociopaths who kill usually look normal and blend into the background, so their behavior often requires psychological profiling before they are caught. Regrettably, profiling only becomes more accurate as the body count rises.