Police investigators say a radical Muslim sect has killed a retired police officer and a market trader in northern Nigeria, the latest targeted shootings blamed on the group.

Borno state police commissioner Ibrahim Abdu told The Associated Press on Monday that the killings were carried out by motorcycle-riding gunmen from the Boko Haram sect. The shootings Sunday night left another person wounded.

Boko Haram — which means “Western education is sacrilege” - attacked police stations in July 2009, sparking a violent military and police crackdown. More than 700 died.

Police blame the group for gunning down at least three police officers in recent weeks, sparking fears the sect may be making a comeback in Nigeria’s Muslim-dominated north.