Africa News Tonight: US President Biden passes the torch, rights groups criticize Zimbabwe detentions, Nigeria police hunt kidnap victims

A month after announcing that he would not seek reelection, President Joe Biden addressed the Democratic National Convention Monday evening and passed the torch to Vice President Kamala Harris as the party's new presidential nominee. Human rights organizations are reacting angrily after Zimbabwe's ruling party acknowledged that more than 100 activists were recently detained to keep them from protesting during a Southern Africa Development Community summit. Police in Nigeria are searching for 20 medical students who were kidnapped on their way to a medical convention.