Karen McWatters

Karen McWatters testified for the prosecution on Day 27 about watching the marathon with her friend Krystle Campbell near the Boylston Street finish line. Under Nadine Pellegrini's questioning, she recalled looking at her phone and then finding herself on the ground amid smoke and screams. She heard another explosion and, despite severe leg pain, moved toward Campbell and held her hand until it went limp. She never saw Campbell alive again.

McWatters described emergency assistance, treatment at Massachusetts General Hospital and a below-knee amputation after doctors tried to save her leg. She believed the amputation occurred after two days but was uncertain about the timing. Her account included two weeks in the hospital, rehabilitation, therapy and prostheses used for swimming and exercise. She also explained that she learned several days later that carrying Campbell's phone had caused hospital confusion: people believed Campbell was in surgery while McWatters's family and friends searched for her.

Photographs helped develop her account of the spectator location and emergency response. The court admitted Exhibit 15 and admitted Exhibit 17 over the defense's objection noted in its papers; Exhibits 18 and 16 were displayed. McWatters acknowledged limits in her observations and medication-affected hospital memory. Her testimony addressed the explosions' effects and her injuries rather than identifying who caused the blasts. The defense declined questioning.

On Day 67, McWatters also addressed the court during the sentencing victim-impact statements, remembering Campbell.