The state-run radio reported that three of the victims were shot dead, including the bar owner, when unidentified gunmen stormed a bar at Nyatubuye village at about 19:30 (17:30 GMT).
The radio indicated that the fourth victim was killed by unidentified gunmen who shot him dead at his house at Muyange-Kavumu village at about 21:00 (19:00 GMT).
Meanwhile, the radio reported that another attack targeted the residence of a primary school director at Gozi, still in Mugamba district, without making casualties.
In the same night, another gunmen attack targeted the house of a teacher at Mwumba secondary school without either making casualties.
Some southern parts of Burundi – mainly Mugamba district – and the capital Bujumbura have been facing insecurity since April 2015 when Burundian President Pierre Nkurunziza announced the controversial decision to run for a third term which he eventually won in a presidential election boycotted by main opposition candidates in July. Enditem