Chauvin, who is serving a 21-year sentence at a federal prison in Arizona, filed the request without a lawyer. He says Dr. William Schaetzel, of Topeka, Kansas, told him that he believes Floyd died not from asphyxia from Chauvin’s actions, but from complications of a rare tumor called a paraganglioma that can cause a fatal surge of adrenaline. The pathologist did not examine Floyd’s body but reviewed autopsy reports.