The Sri Lankan brothers accused of committing human rights violations during the country’s bloody civil war are now back in power as president and prime minister.

Gotabaya Rajapaksa, who won Sri Lanka’s presidential election Sunday, swore in his older brother Mahinda as prime minister Thursday – marking the first time ever that siblings have occupied the country’s top two political posts, Reuters reports.

Mahinda has been prime minister twice and was Sri Lanka’s president from 2005 to 2015, while Gotabaya served as his defense chief, Reuters added.

In 2009, the two led the effort to defeat Sri Lanka’s Tamil Tiger rebels, ending a 26-year civil war that resulted in at least 100,000 deaths.

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Yet in the conflict’s final stages, thousands of Sri Lankans were said to be tortured or killed after disappearing – and in the years after it was over, journalists, activists, and opponents of the brothers vanished as well, according to the BBC.

Rights groups and minorities have accused the brothers of committing human rights violations and fear ethnic tensions could flare up again now that they have returned to power, Reuters reports.

But the Rajapaksas have denied any wrongdoing.

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Mahinda will serve in his new position until parliamentary elections next year. His path to becoming prime minister opened up after Ranil Wickremesinghe – the former holder of the post -- resigned following the defeat of his party’s candidate in the presidential elections.

Both brothers are expected to help boost Sri Lanka’s economy, which has been in a slump since a series of suicide bombings there left 250 people dead on Easter Sunday this year.