On the basis of four ‘irregular’ extradition cases, the author demonstrates that states sometimes violate generally accepted rules of extradition law. Legitimate grounds for the refusal of, as well as procedural impediments to extradition are evaded -for instance by simply kidnapping the individual involved. Also, the so-called ‘disguised extradition’ is used by states, when expelling a person in stead of extraditing him, but in fact accomplishing the same result. Despite such apparent failures in the procedure of obtaining an individual (‘male captus’), states maintain that the individuals can nevertheless be legitimately tried (‘bene judicatus’). According to the author, these practices are incompatible with certain general principles of international law.