One of the most anticipated witnesses of Derek Chavin’s trial, the Hennepin County medical examiner who performed the initial autopsy of George Floyd, testified on Friday that while police restraint was the main cause of Mr. Floyd’s death, drug use and heart disease were contributing factors.

The medical examiner, Dr. Andrew Baker, declared Mr. Floyd’s death a homicide in his autopsy, but had made several statements leading up to the trial that could have complicated the arguments of the prosecution, particularly in relation to Mr. Floyd’s drug use. In all, his testimony maintained that Mr. Chauvin’s actions — pinning Mr. Floyd to the street for nine and a half minutes — were the primary causes of death.

Jurors also heard from Dr. Lindsey Thomas, a forensic pathologist who helped train Dr. Baker. During her testimony, Dr. Thomas said she believed that Mr. Floyd died from a deprivation of oxygen caused by the restraint of Mr. Chauvin, the former police officer charged with murdering Mr. Floyd. Here are the highlights from Day 10 of the trial.

• Though multiple contributing factors may have contributed to Mr. Floyd’s death, Dr. Baker said he believed that the primary cause of death was the same as he wrote in his initial autopsy: “cardiopulmonary arrest complicating law enforcement subdual, restraint, and neck compression.” In simpler terms, Dr. Baker said that Mr. Floyd would not have died were if not for the actions of Mr. Chauvin. Still, he said that the compounding factors, including heart disease, played a role as well. Dr. Baker agreed with a statement from the defense that methamphetamine was hard on the heart; a toxicology report found methamphetamine and fentanyl in Mr. Floyd’s system, and pill fragments found at the scene contained the same drugs. Dr. Baker said he found no pill fragments in Mr. Floyd’s stomach.