The seven-member strong panel led by Deepak Chakraborty, a director of the Local Government Division for Chattogram region, visited the scene on Thursday, according to Monjur Alam, chief of Baghaichhari Police Station.
They visited the Noy Mile Area around 8am. Later they spoke to the victims in the Upazila Health Complex and several election officials who were inside the vehicle during the gun attacks, said Alam.
On Wednesday, police had filed a case accusing 50 unidentified men over the incident.
On Mar 18, unidentified gunmen in Rangamati shot dead the seven after the end of the second phase of the Upazila election boycotted by an organisation of Chattogram Hill Tracts people.
At least 11 others were injured when the gunmen carried out the attack in Noi Mile area on Baghaichhari-Dighinala road.
The government later formed the investigation committee and asked it to determine the reasons for the killings, extent of damages, and recommend ways to prevent a repeat of violence in the area.
The committee was also asked to submit a report within 10 workdays.