The investigation report has found negligence of police in the gruesome killings of four children in the village Sundrateki under Bahubal upazila of Habiganj.
Following the probe report, Bahubal police station Sub-Inspector Ziaur Rahman Zia was suspended.
The report also recommends action against OC (investigation) Abdur Rahman for negligence in duty.
Probe body chief Additional Police Super Shahidul Islam told the reporters that the report was submitted to Police Super Joydeb Kumar Bhadra on Sunday afternoon.
Four children Shuvo, 8, his cousin Tajel Miah, 10, Monir Miah, 7, and Ismail Hossain, 10, disappeared on February 10 as they went to watch a football match to nearby Uttar Bhadeshwar village.
The locals found their bodies from the bank of river Karangi on February 17.
Police arrested neighbour Abdul Ali Bagal, his sons Jewel and Rubel, Azizur Rahman Arzu and Bashir Miah in suspicion of being involved in the incident.
On February 21, Jewel confessed that he and his family members were involved in that dreadful incident. He also gave names of more people who were involved in the gruesome killings.