LONDON (Reuters) – The teenage sister of a British man killed in a militant attack in Manchester was on Thursday awarded top marks in national exams she sat just in the days after learning her brother had died.

Nik Hett’s brother Martyn was among the 22 people killed in May when a suicide bomber blew himself up as crowds streamed out of the Manchester Arena following a pop concert by U.S. singer Ariana Grande.

Another teenager, 16-year-old Ines Alves, also achieved an A grade in a paper she sat just hours after escaping a deadly fire in a London tower block.

The pair were among thousands of teenagers across the country to open the results on Thursday from their GCSEs — national exams taken by most British teenagers in the academic year when they turn 16.

“Floored” by his younger sister’s bravery, Nik’s other brother Dan Hett took to Twitter to applaud her for scoring some of the highest marks available despite the circumstances.

“Under the most horrific conditions, after going through (and continuing to go through) it all, she didn’t skip a beat,” he wrote. “My kid sister is the toughest person I have ever met.”

He added that Nik’s school had told her she did not need to sit her GSCEs and that provisional grades from tests taken previously could be used as her final results.

“Nik said: nope! And took the lot,” he continued. “Sleeves rolled up, get it done.”

“She got her results today. Eleven A* grades. I have never been more proud or amazed by anyone.”

In London, Alves scored an A in chemistry – an exam she sat at 0900 (0800 GMT) on June 14, just hours after the Grenfell Tower building caught fire, killing around 80 people and destroying her family home.

She also scored a grade 9 in maths, putting her in the top 3 percent of the country.

A and A* grades are equivalent to a 7, 8 or 9 in the exams, with 9 being the highest mark achievable under a new grading system being introduced this year.