Where a defense has been put forward as discussed above,[16] the prosecution are essentially in the position of having to "disprove a negative"[17] by showing that malware was not responsible. This has proved controversial, with suggestions that "should a defendant choose to rely on this defense, the burden of proof (should) be on that defendant".[18] If evidence suggest that malware was present and responsible, then the prosecution need to seek to rebut the claim of absence of defendant requisite mens rea.