They probably thought that the other clerics were heretics or apostates from Islam. Both of these offenses carry the death penalty in Islamic law.
“Ugandan Muslim clerics sentenced to life for terrorism,” Reuters, August 22, 2017 (thanks to The Religion of Peace):
Kampala – A Ugandan court on Tuesday sentenced a Muslim group leader and three associates to life in prison after their conviction on terrorism charges related to threats to harm rivals, a judicial official said.
Over the last few years more than a dozen senior Muslim figures in Uganda have been killed, in most cases gunned down by unknown assailants riding on motorcycle taxis.
Sheikh Mohammad Yunus Kamoga, who heads Tabliqs, a radical Muslim faction, and 13 others were arrested and charged with terrorism and the murder of some other Islamic group leaders.
On Monday six of them were convicted on the terrorism charges but all were cleared of murder.
In a high court session on Tuesday, Kamoga and three others were sentenced to life while two associates were given 30 years each, according to judiciary spokesman Solomon Muyita.
The court acquitted the group of murder because prosecutors failed to place any of them at the scenes of crime, he said….