Whether a petitioner can be denied discovery necessary to learn the circumstances of the government's spoliation of potentially exculpatory evidence in federal habeas proceedings

QUESTIONS PRESENTED 1. When, if ever, can a petitioner be denied the discovery necessary to learn the circumstances of counsel for respondent’s spoliation of potentially exculpatory evidence which the petitioner was seeking to have DNA tested, in the course of proceedings on a federal habeas corpus claim for prosecutorial suppression of evidence? 2. Does spoliation of potentially exculpatory evidence by one part of a prosecution team impact the credibility of others on the team?