On 22 May 2017, Spain's Constitutional Court (Tribunal Constitucional) has accepted to hear a complaint against the closing of investigations into incidents of systematic torture and cruel, inhuman and degrading treatment of detainees occurring in Guantánamo after 2001. In December 2016 ECCHR, CCR and its cooperation attorneys in Spain had filed a constitutional complaint, after in November 2016 the Supreme Court upheld the decision of the investigating judge to close the investigations. The Spanish judiciary had been conducting investigations into the US torture program since 2009. Spain revoked its laws on prosecuting torture under the universal jurisdiction principle in 2014. However, the parties presented evidence not only against US officials, but also Spanish accomplices in the Guantánamo investigation, which broadens the jurisdiction for the Spanish judiciary to investigate and prosecute the cases. The Constitutional Court decision is now pending with an unknown schedule.
In May 2009 and again in April 2010, Judge Velasco, who is responsible for the investigation of the Bush Six case, issued formal rogatory letters to the United States seeking information regarding any pending investigations in the US that would render the Spanish complaint unnecessary. The Obama administration repeatedly ignored the request, while, as the WikiLeaks cables suggest, they acted to undermine the legal process through political means. In January 2011, Judge Velasco issued a final order for compliance, setting a March 1 deadline, to which the US finally replied.
In its submission, the Department of Justice requests that the Spanish Court refer the case to the United States for further review, as it claims to be fully capable of investigating and prosecuting the alleged crimes. Although the US failed to cite any evidence that it has, in fact, undertaken such investigations or prosecutions against mid or high-level US officials, on 13 April 2011 Judge Velasco temporarily stayed the Bush Six case in Spanish courts, referring it back to the United States "for it to be continued". On 19 April 2011, an appeal was filed against Judge Velasco’s ruling. The Spanish National Court declined to order the resumption of the investigation. After a further appeal was rejected by the Spanish Supreme Court, a petition for review was filed and is now pending before the Spanish Constitutional Court. ECCHR and CCR, supported by a range of former UN Special Rapporteurs, members of the US military, legal experts and human rights organizations experts filed a brief on 25 September 2012 setting out the continued failure of US authorities to initiate prosecutions in the case.