KANSAS CITY, Kan. — A court-appointed official looking into the taping of attorney-client meetings at a federal detention center in Kansas says the state’s U.S. attorney’s office is no longer cooperating with his investigation.

Special Master David R. Cohen said in a report obtained by KCUR Radio that he received a 24-page letter last month from the U.S. attorney’s office stating that it will no longer provide him with information and documents as part of his investigation of claims involving the Leavenworth Detention Center.

The decision may heighten suspicions that the U.S. attorney’s office is concealing information about the tapings from criminal defense lawyers, many of whom have filed motions to dismiss cases on the grounds that the Sixth Amendment rights of clients were violated.

At least two class-action lawsuits have been filed by attorneys on behalf of former detainees, both seeking at least $5 million in damages from the operator of the prison, CoreCivic Inc., and the company that provides the prison with phone services, Securus Technologies.

Both companies have denied wrongdoing. Cohen, in his report, commended both for their cooperation.

But the report also cites the 24-page letter from Steven D. Clymer, a federal prosecutor in New York appointed to act as the contact with Cohen after the U.S. attorney’s office in Kansas concluded it might have a conflict.

The letter cites several reasons for declining Cohen’s requests for information, asserting that there is no evidence suggesting there were any constitutional violations or that recording "was conducted at the direction of the OUSA (U.S. Attorney’s Office)."

Jim Cross, spokesman for U.S. Attorney Tom Beall, declined to comment, saying the office doesn’t publicly discuss pending litigation.

The prison recordings probe grew from an earlier criminal investigation into contraband at the detention center. Many of the people held at the facility are defendants awaiting trial who have not been convicted.

The court-appointed special master has reported that law enforcement obtained 188 recordings of attorney-client phone calls from the facility, including 54 marked "private" that should not have been available.

Cohen, in his report to U.S. District Judge Julie Robinson, said the decision not to produce responsive information "is a drawing of shades against sunlight," and may be against the U.S. attorney’s office’s own interests.

Cohen said that so far, his investigation found just one instance where the U.S. attorney requested video recordings of meetings between inmates and their attorneys "and the OUSA did not actually view any such meeting."