Rights activists have expressed concern about a fair investigation into the case filed over police firing during demonstrations by workers of SS Power I Plant project in Chattogram's Banshkhali upazila eight days ago.

They expressed the concern after noticing discrepancies between versions of witnesses and injured and the description of the incident in the case statement.

The April 7 incident left seven workers dead and at least 19 people injured.

The Daily Star has obtained a copy of the case statement. Sub-Inspector Rasheduzzaman Beg of Gandamara Police Outpost had filed the case with Banshkhali Police Station on April 18.

The SI lodged the case against 2,500 unidentified people on charges of attacking law enforcers and killing workers.

Faruk Ahmed, chief coordinator of the power plant, filed another case accusing 22 named and 1,040 unnamed people over torching vehicles and looting valuables.

Rasheduzzaman in the case statement said a group of about 300 workers abstained from work at the project site on April 16 to press home their nine-point demand. However, another group of workers agreed to continue work.

On April 17 morning, around 2,500 workers gathered at the project site in a procession. At one stage, locals entered the site breaking through the barbed wire fence at the instigation of outsiders, said the complainant.

He said the armed workers and outsiders launched an attack on Chinese workers and law enforcers. The agitating workers started vandalising vehicles and setting those on fire. They pelted police with brick chunks.

Rasheduzzaman said shots were fired at police from the workers' quarters. He said police fired rubber bullets, teargas shells and "china bullets"to save lives, properties and government firearms. The plaintiff said police opened fire following his directive.

He mentioned that five workers were killed in a "shootout between workers and outsiders".

However, witnesses and injured workers told The Daily Star that police opened fire on them indiscriminately after some agitating workers pelted law enforcers with brick chunks. At least six witnesses said the causalities occurred following indiscriminate firing by police.

Akhter Kabir Chowdhury, president of Chattogram unit of Shushashoner Jonno Nagorik (Shujan), said all the seven killed were project workers and no outsider was killed.

"Police are yet to recover any arms from workers or outsiders. Besides, no policeman was hit by bullets during the incident. So, there are discrepancies in the case statement."

He said preparing such a case statement is a mockery of workers' lives. The rights activist said police could write such an FIR as there was no transparency and accountability.

Asked about discrepancies in the FIR, Officer-in-Charge of Banshkhali Police Station Shafiul Kabir said, "The SI wrote the case statement and I just put my signature on it. He can tell you better about it as he was on the spot."

Asked why he did not go through the FIR before signing it, the OC said if there was any incorrect information or discrepancies in the case statement, it would be detected during the probe.

The workers on April 17 were staging demonstrations to press home their demands, including payment of arrears, pay hike, an hour's break each for iftar and offering prayers, and payment of two Eid bonuses.

S Alam Group is setting up the 1,224 megawatt coal-fired power plant at Pachsim Gandamara of Banshkhali. It is a joint venture of six companies of S Alam Group, SEPCOIII Electric Power Construction Corporation, China and HTG Development Group Co Ltd, China, according to the official website of S Alam group.