The murder trial of Derek Chauvin continued on Monday morning (April 5) with testimony from Dr. Bradford Wankhede Langenfeld, the Hennepin County Medical Center physician who pronounced George Floyd dead.

Floyd was taken to the hospital on the evening of May 25 and was treated for 30 minutes, Langenfeld said. The emergency physician believed Floyd had been in cardiac arrest for around an hour and ultimately pronounced him dead after assessing he had “virtually no cardiac activity.”

Prosecutors asked Dr. Langenfeld if he believed Floyd’s lack of oxygen caused his fatal cardiac arrest.

“That was one of the more likely possibilities I felt at the time, based on the information I had,” he answered. “It was more likely than the other possibilities.”

The doctor also testified that the paramedics’ report did not say whether or not Floyd received CPR from police or any bystanders when he first went into cardiac arrest.

“I did not receive a report that Mr. Floyd had received standard CPR, no,” he added.

Langenfeld said that Floyd’s chance of surviving the cardiac arrest decreased by 10 to 15 percent every minute he wasn’t given CPR.

“It’s well known any amount of time a patient spends in cardiac arrest without CPR markedly decreases the chance of a good outcome,” he said.

Paramedics also previously testified that police could have given Floyd CPR when he went into cardiac arrest, but did not.

“There’s no reason Minneapolis [police] couldn’t have started chest compressions,” paramedic Derek Smith said in court on Thursday (April 1).

Today marks the sixth day of Chauvin’s murder trial with court continuing in its second week. CNN notes that Dr. Langenfeld is the 20th witness prosecution has called so far. While the first week of Chauvin’s trial centered around Floyd’s final moments and emotional testimonies from witnesses, prosecutors are now expected to shift the focus to the legality of Chauvin’s actions and prove that they should be considered as murder, CNN adds.

Last week, both the head of the Minneapolis Police’s homicide unit and Chauvin’s supervisor said his use of force against Floyd was excessive. Lt. Richard Zimmerman called Chauvin’s actions “totally unnecessary” and Former Sgt. David Pleoger said Chauvin should have taken his knee off of Floyd as soon as he stopped resisting.

Tune into the ongoing trial below.