18 It is discussed whether, in addition to ‘statements’, Article 15 also applies to any other type of evidence derived therefrom and if it covers only the direct or primary results of torture or also the so-called ‘fruits of the poisonous tree’, ie derivative or secondary evidence to which the coerced statements have led to.26
19 In the literature there seems to be no consensus on this issue.27 The omission of an explicit reference to evidence derived from torture and the fact that the IAPL draft did indeed include a mention to ‘any other evidence derived therefrom’, which was however not reproduced in the subsequent drafts, seem to suggest that Article 15 does not apply to the fruits of the poisonous tree.28 On the other hand, such an interpretation would undermine the preventive rationale of the provision. Making tainted secondary evidence (p. 422) admissible would in fact represent a considerable incentive to use coercive methods of interrogation, as well as more generally put at risk the principles of fair trial and integrity of proceedings.
20 The Committee appears to support an extensive interpretation of Article 15. For example, in its Guidelines on initial reports the Committee explicitly requires States Parties to report on ‘whether derivative evidence is admissible, if applicable in the State party’s legal system’,29 thus implicitly considering that Article 15 extends to indirect evidence. The issue had been also addressed in a 1998 Concluding observations to Germany, where the Committee recommended ‘that further legislative attention be paid to the strict enforcement of Article 15 of the Convention and that all evidence obtained directly or indirectly by torture be strictly prevented from reaching the cognizance of the deciding judges in all judicial proceedings’.30 Similarly, in GK v Switzerland the Committee has taken into account evidence that had been found following a search conducted on the basis of the testimony extracted by torture (firearms and explosives),31 thus backing the view that the word ‘any statements’ includes also other evidence.32
21 The same conclusion is reached by other international and regional human rights bodies. In its General Comment No 32, the HRC has clarified that Article 7 CCPR applies to ‘statements or confessions or, in principle, other evidence obtained in violation of this provision may be invoked as evidence in any proceedings covered by article 14’.33 The ECtHR held that ‘incriminating evidence—whether in the form of a confession or real evidence—obtained as a result of acts of violence or brutality or other forms of treatment which can be characterized as torture—should never be relied on as proof of the victim’s guilt, irrespective of its probative value’, thereby acknowledging the relevance of evidence other than statements.34
22 But even if one concluded that the rule applied also to derivative evidence, other questions of interpretation would arise, above all, if Article 15 imposes a blanket exclusion to all derivative evidence. Though the Committee has never pronounced itself on this issue, it shall be noted that in some legal traditions, the fruits of the poisonous tree doctrine applies with some limitations, and evidence that is discovered through an independent source by the police or which discovery was inevitable may be considered admissible in proceedings.35However, considering the particular seriousness of the violation and the absolute nature of the prohibition of torture, the ECtHR has taken a different approach when it comes to torture tainted evidence. For example, in contrast to evidence obtained in violation of other Convention’s provisions, the ECtHR, attaching particular (p. 423) considerations to the use in criminal proceedings of evidence obtained in violation of Article 3 ECHR, has concluded that evidence obtained as a result of torture—whether in the form of statements or real evidence—would always and automatically render unfair the whole criminal proceedings, regardless of the probative value of the evidence and irrespective of whether they had a decisive impact on the final conviction. For the ECtHR,
[a]ny other conclusion would only serve to legitimate indirectly the sort of morally reprehensible conduct which the authors of Article 3 of the Convention sought to proscribe or, as it was so well put in the United States Supreme Court’s judgment in the Rochin case (see paragraph 50 above), to ‘afford brutality the cloak of law’.36
23 A more restrictive stance is taken by the ECtHR only for what concerns real evidence obtained as a result of inhuman and degrading treatment, for which it has decided to leave open the question as to whether such evidence would render the trial automatically unfair, and decided to apply the standard test assessing the circumstances of the individual case instead.37 This point has been further clarified by the ECtHR in Gäfgen, where the Court stated that ‘the application of the fruit of the poisonous tree doctrine should be limited only to real evidence that has a causal link with the inhuman and degrading acts’.38
24 In light of the foregoing, it is preferable to interpret Article 15 as applying also to indirect evidence, especially in light of the preventive rationale of such provision. As put by the ECtHR, any other conclusion would only serve to legitimate indirectly the conduct which Article 15 CAT aims to prohibit, and represent an incentive for law enforcement personnel to use coercive methods and thus undermine its preventive scope.