So there they were, staring at the just-received and damning toxicology report that blew to smithereens the whole prosecution theory that the police had killed Floyd. To their undoubted dismay, Dr. Baker, the chief medical examiner, had to concede that at 11 ng/mL, Floyd had a fatal level of fentanyl under normal circumstances. He also conceded that the fentanyl overdose can cause pulmonary edema, a frothy fluid build-up in the lungs that was evidenced by the finding at autopsy that Floyds lungs weighed two to three times normal weight.