A former interior minister of Gambia was going on trial Monday in Switzerland on charges including crimes against humanity for his alleged role in years of repression by the west African country’s security forces against opponents of its longtime dictator.

Advocacy groups hailed the trial of Ousman Sonko, Gambia’s interior minister from 2006 to 2016 under then-President Yahya Jammeh, as an opportunity to reach a conviction under “universal jurisdiction,” which allows the prosecution of serious crimes committed abroad.

Sonko was taken Monday in a police van to Switzerland’s federal criminal court in southern Bellinzona.

He applied for asylum in Switzerland in November 2016 and was arrested two months later. The Swiss attorney general’s office said the indictment against Sonko, filed in April, covers alleged crimes during 16 years under Jammeh, whose rule was marked by arbitrary detention, sexual abuse and extrajudicial killings.

“The trial of Ousman Sonko is another major step in the search for justice for victims of brutal crimes and their families committed under Jammeh’s rule,” said Sirra Ndow, coordinator of the Jammeh2Justice campaign.

Swiss prosecutors say Sonko is accused of having supported, participated in and failed to stop attacks against regime opponents in the country, which juts through neighboring Senegal. The alleged crimes include killings, acts of torture, acts of rape and numerous unlawful detentions, Swiss authorities say.

Philip Grant, executive director at TRIAL International, which filed a case in Switzerland against Sonko before his arrest, said he was “the highest-level former official to be tried under the principle of universal jurisdiction in Europe.”