BOSTON (AP) Laura Nowacki had rushed to help the shooting victims at Sandy Hook Elementary School in Newtown, Conn. As a first responder, the pediatrician was stunned at the horror she encountered.

Just four months later, she hurried out of Boston with her husband and four children, anxious to keep them safe after the deadly explosions near the finish line of the historic marathon she had just completed.

The race was supposed to help Nowacki recover from the shock of the Newtown shootings that killed 20 children and six educators and from which her 10-year-old daughter fled uninjured. Instead, it brought the painful memories back.

About 40 minutes after she completed the Boston Marathon on Monday, two explosions near the finish line killed three people and injured more than 170.