Wiretappings in a Guatemala tax corruption case indicate that a judge-bribing scheme to free some of the accused from jail may have reached the country's supreme court.

Recorded telephone calls obtained by The Associated Press show backdoor negotiating between businessman Luis Mendizabal, lawyers and suspects to free those detained in a scheme to defraud the state of millions of dollars in customs payments. In a call dated April 16, Mendizabal tells detainee Javier Ortiz to remain calm because he will be out soon.

"Blanca Stalling is behind it and they have very good communication," Mendizabal said.

Stalling is a member of Guatemala's supreme court. Repeated calls to Stalling for comment went unanswered on Sunday.

The tax fraud scheme has rocked Guatemala's political class since it was announced in April and has become the largest corruption scandal for a sitting president. It already has cost Guatemala's vice president her job. Roxana Baldetti resigned Friday and gave up her immunity from possible prosecution, a move lauded by President Otto Perez Molina.

Baldetti's former private secretary, Juan Carlos Monzon Rojas, is alleged to have been the ringleader of a scheme to defraud the state of millions of dollars by taking bribes in exchange for lower customs duties. Monzon is a fugitive whose last known whereabouts were overseas, and he is currently being sought by authorities.

In a separate but related case in which Mendizabal is named, five lawyers were arrested on Friday for allegedly bribing a judge to free suspects jailed in the corruption case. Prosecutors and a U.N. investigative commission said the attorneys paid Judge Marta Sierra Stalling to release three suspects on bail, including Ortiz. He was later re-arrested after authorities learned of the bribery scandal.

Sierra Stalling has not been charged because of judicial immunity, but prosecutors have asked the Supreme Court to revoke her immunity. She is the sister-in-law of Supreme Court Justice Blanca Stalling.

Authorities say Mendizabal ran a clothing boutique where the leaders of the fraud ring met to plan the operation. He also is a fugitive.