Most detective novels of the known Petersburg authoress Elena Valentinovna Топильской, in the past - investigator on especially important businesses, served basis of scenario of the first eight seasons of popular tele-serial of "Secret of the investigation" sanctified to the severe labour week-days of workers of district office of public prosecutor. So, novel "Criminalistics on Fridays" - about that, how it is difficult to investigate business about the crimes accomplished by a man without a person. Choosing places for attacks, he writes an enigmatic acrostic, that leads away an investigator Maria Швецову in the past hiding frightful skeletons in the cupboard of a kill man. They and help to find the real criminal. Recitals are presented also of the most interesting cases from inquisitional practice of author.