The woman whose shocked face amid the carnage of the Boston Marathon bombings became a symbol of the terror on Monday has been revealed as a triathlete whose sister lost a leg in the tragedy after they went to the race to cheer on their mother.

Nicole Gross, 31, had her left leg broken in two places, suffered a fractured right ankle and a severed Achilles’ tendon.

Doctors were forced to amputate the leg of her sister, Erika Brannock, a 29-year-old elementary school teacher. Her right leg suffered a compound fracture, a broken ankle and a broken foot. 

Haunting: This image of North Carolina personal trainer Nicole Gross was published around the world

Tragedy: Erika Brannock, left, lost her left leg and her right leg was badly broken. Nicole Gross, right, broke her left leg in two places, suffered a fractured right ankle and a severed Achilles' tendon. They were watching their mom, Carol Downing, run

Horror: Nicole Gross, right, is seen at the Boston Marathon with her mother Carol Downing just hours before the bomb attack that made her a haunting symbol of the bomb blasts

The Charlotte Observer reports that both Gross and Brannock are recovering at Boston hospitals from the horrific injuries. 

The haunting image of Mrs Gross, a fitness instructor in Charlotte, North Carolina, and a noted triathlete, was printed on the front pages of newspapers around the world, including both the New York Post and New York Daily News. 

'She remembers it all and just wishes that she didn’t,' her mother Carol Downing, 59, told the newspaper.

She sits dazed and battered, missing one shoe, and surrounded by pools of blood and horrifically injured race watchers. 

Both Mrs Gross and Mrs Brannock had flown into New England to cheer on their mother as she completed her first Boston Marathon.  

 

Safe: Michael Gross, a former Charlotte firefighter, was treated for minor injuries and released from the hospital. Mrs Gross is still recovering

Mrs Gross had helped train her mother for the grueling race and wanted to make certain she saw her finish. 

Mrs Downing was still few blocks from the finish line when the twin blasts went off. Panic set in when she realized that she could not contact either of her daughters or Mrs Gross' husband Michael.

Mrs Gross is regarded as one of the best female triathletes in North Carolina, friends say, and has competed in the grueling Kona Ironman in Hawaii - one of the toughest endurance events in the world. 

'I think a lot of people are intimidated by her because she’s really good looking, she’s smart, she’s a good coach, she’s popular in the sense that a triathlete can be,' fellow triathlete James Haycraft told the Observer. 'I don’t think anyone I know has ever had a negative thing to say about her.'