Lenin V. Perez, a former president of the Tampa National Association of Letter Carriers, died Tuesday at the Pinellas County jail while awaiting sentencing on federal charges for his role in a workers compensation kickback scheme. Perez, 70, was found unable to move or speak and died in his housing area in the jail's medical building, officials said. Efforts to treat him were unsuccessful. Perez had been held at the jail for the U.S. Marshals Service since April, when a judge revoked his bail on 2015 charges. He pleaded guilty earlier this year to conspiring to receive kickbacks for referring injured federal workers to AmeriMed Diagnostic Services Inc. for treatment. In July, U.S District Judge James S. Moody Jr. entered a judgment against him for more than $2.1 million. He was scheduled to be sentenced Nov. 15 and faced up to five years in prison. Three others were also charged. Perez had health issues back in April, when a magistrate judge ordered that he get necessary medical attention while in jail. He was transported to a local hospital on Oct. 7 after complaining of back pain. A week later, he was put in the jail's medical building for both back pain and mobility issues. Officials said Perez showed no obvious sign of injury, and his death didn't appear suspicious. The Medical Examiner's Office will conduct an autopsy.