GENEVA — Switzerland's Federal Supreme Court has upheld a 20-year jail sentence for former Liberian warlord Alieu Kosiah, rejecting his appeal in a verdict dated September 28 and published on Friday, October 30, the court said in a statement reported by AFP. The ruling closes the case and makes final the first war-crimes conviction ever handed down by a Swiss civilian court — and, the legal organisation Civitas Maxima said, the first conviction anywhere of a Liberian for war crimes committed during the country's civil wars.

Source: Reuters

The court rejected Kosiah's appeal against his conviction for violations of the laws of war committed between 1993 and 1995 during the first Liberian civil war, and the maximum 20-year custodial sentence stands. But it acquitted him of crimes against humanity, on a strict application of the principle of non-retroactivity: that offence was introduced into Swiss law in 2011 and, the court ruled, cannot be applied to acts committed before then.

20 yearsMaximum sentence upheld — Kosiah's war-crimes conviction is now final
1993–1995Period of the crimes, as commander of the ULIMO rebel group in Liberia's first civil war
17 civilians + 2 soldiersPeople the 2021 court found Kosiah ordered or took part in killing, alongside rape and use of a child soldier
~250,000 deadEstimated toll of Liberia's back-to-back civil wars, 1989–2003

A case built over a decade

Kosiah, now 51, was a commander of the United Liberation Movement of Liberia for Democracy (ULIMO), which fought against then-president Charles Taylor's army. Switzerland's Federal Criminal Court found him guilty in 2021 of a series of war crimes — ordering or participating in the killing of 17 civilians and two unarmed soldiers, rape and deploying a child soldier; Reuters' summary of the original verdict also listed cannibalism among the crimes. An appeals chamber upheld the 20-year sentence in 2023 and, for the first time in Swiss history, also convicted him of crimes against humanity — the part of the verdict the Supreme Court has now reversed.

The prosecution was brought under the principle of universal jurisdiction, which allows a country to try grave crimes committed elsewhere. Civitas Maxima, the organisation behind the case, said Friday's decision definitively confirms the first war-crimes conviction by a Swiss civilian court and the first conviction worldwide of a Liberian national for the civil wars, in which around 250,000 people died between 1989 and 2003.

What the ruling could mean beyond Kosiah

Swiss reporting, including by SRF, has noted that the same non-retroactivity question arises in the case of former Gambian interior minister Ousman Sonko, whose appeal judgment is due on December 1 — and that the Kosiah reasoning could force a significant reduction in his sentence, because his case cannot rely on war-crimes charges in the same way. What happens next is procedural: Kosiah's sentence is final in Switzerland, and attention turns to the Sonko judgment in December for the first test of how far Friday's ruling reaches.

Sources: Reuters, October 30, 2026 — the Supreme Court's confirmation of the verdict and sentence and the reversal of the crimes-against-humanity conviction; AFP, October 30, 2026 — the court's statement, the September 28 verdict date and the 2021 findings; Civitas Maxima, October 30, 2026 — the first-conviction significance; SRF via Daily Alpine, October 30, 2026 — the possible effect on the Sonko appeal.