ORLANDO, Fla. — A jury has been chosen in the trial of the widow of the man who shot and killed 49 people at the Pulse nightclub in Florida.

U.S. District Judge Paul G. Byron, federal prosecutors and defense attorneys picked 12 members and six alternates on Monday.

The trial of 31-year-old Noor Salman, widow of shooter Omar Mateen, is scheduled to begin Wednesday. Salman is charged with aiding and abetting Mateen. She’s pleaded not guilty.

At the time of the attack in June of 2016, it was the worst mass shooting in modern U.S. history. It was surpassed last October by the fatal shooting of 58 people in Las Vegas.

Mateen was killed hours after the attack at the nightclub in Orlando.