A Ugandan-American man was sentenced to death on Thursday over the murders of four young children he stabbed to death at a kindergarten in Uganda’s capital.

Christopher Okello Onyum was arrested on April 2 as he tried to flee the day care centre in Kampala where he murdered the children aged 15 months to two-and-a-half years.

Prosecutors said Onyum, who holds Ugandan and US citizenship, confessed to the crime, believing the “human sacrifice” would help him become rich, though he eventually...