A note on the Globe’s stories Sunday about the Boston Marathon bombing.

The Aurora, CO, cinema shooting last July, which killed 12 people and injured 58 others, played a key role in preparing Brigham and Women’s Hospital in Boston to treat the onslaught of victims injured in the explosions at the Marathon finish line on April 15.

Here is an audio timeline of the mass shootings in Aurora.

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Dr. Richard Zane, head of the emergency department at the University of Colorado Hospital and a former Brigham doctor, created the timeline and shipped it to Dr. Ron Walls, head of the Brigham ER, last September. It shows the speed with which the Denver hospital had to treat scores of critically injured victims. After Walls listened to the 911 calls, he strengthened the Brigham’s emergency medical response plan.