At least four ethnic Hazara people were shot dead when unidentified gunmen opened fire on their vehicle near Balochistan's Mastung area on 19 July.
The police sources said was an incident of targeted killing, reports the Dawn.
The assailants escaped after the killings. The police and other Law Enforcement Agencies (LEAs) personnel reached the site and started an investigation into the incident.
Balochistan has been experiencing violence and targetted killings for more than a decade. More than 1,400 incidents targetting the minority Shia and Hazara community have taken place in the province during the past 15 years.
Previously, Pakistani Sunni Muslim extremist militant group, Lashkar-e-Jhangvi, had been assumed to be behind the sectarian attacks against Hazaras.
Quetta, capital of Balochistan, has seen numerous of these violent incidents.