President Obama announced in May that Mr. Ghailani would be transferred into the civilian system from the naval base at Guantánamo Bay, Cuba, where he had been since 2006. The president said his goal was to try terrorism suspects in federal courts “whenever feasible.”  Mr. Ghailani’s lawyers have indicated that they intend to dig deeply into what happened to their client during his years in detention and to determine how his treatment might affect the federal case against him.  “It appears undeniable,” they wrote, that he “was subjected to harsh conditions and harsh interrogation techniques” while detained in the black sites.  One issue, they said, concerns the admissibility of any statements he might have made.  Another reason for their request, they wrote, involves the death penalty. If the government decides to seek it against Mr. Ghailani, the lawyers said, they want to be able to present “a detailed and accurate representation of the physical sites” where he was held and subjected to harsh treatment as mitigating evidence on his behalf.  Such a presentation would also seem likely to be used in arguments to the government against seeking capital punishment in the first place.  A spokeswoman for the United States attorney’s office in Manhattan had no comment on the filing.  Mr. Ghailani, who has pleaded not guilty, is scheduled to appear in court on Thursday. The death penalty is one issue that may come up.  Last month, Judge Kaplan noted that the Defense Department decided not to seek the death penalty against Mr. Ghailani when he was in the military commission system. The judge suggested that the Justice Department should be able to “let us know very quickly if the death penalty is off the table.”  A version of this article appears in print on , on Page A20 of the New York edition with the headline: Secret C.I.A. Jails an Issue in Terror Case. Order Reprints| Today's Paper|Subscribe
Lawyers for Ahmed Khalfan Ghailani, a man charged in a conspiracy involving Al Qaeda, are seeking to learn more about what happened to Mr. Ghailani in the two years after he was captured.