In the clip which has been circulating on Twitter, Facebook and WhatsApp, one of the officers, armed with an AK-47 rifle, is seen slapping the unidentified man after beating him with a cane.
The Nigerian police have demoted an officer who was filmed slapping a motorist in Emouha, Rivers State, South-south Nigeria.
The exact date of the incident is unknown, but the clip surfaced online around 9 April.
In the clip which has been circulating on Twitter, Facebook and WhatsApp, one of the officers, armed with an AK-47 rifle, is seen slapping the unidentified man after beating him with a cane.
Another officer was also filmed shoving a woman, said to be the man's wife, into a car.
Amidst outrage on social media, the police in Rivers and at the Force Headquarters, Abuja, had condemned the officers' action before they- three of them - were later arrested and taken to Abuja to face administrative trial.
The spokesperson for the Force Headquarters, Muyiwa Adejobi, in a statement on Tuesday, said Adejoh Siaka, the inspector who assaulted the motorist, has been demoted to the rank of sergeant after an administrative trial.
Mr Adejobi, a chief superintendent of police, said one other officer, Ndiwa Kpuebari, a sergeant, was reprimanded for being present at the scene of the incident and not taking any action to discourage such "inappropriate and shameful act".
"However, one Inspector Friday Obaka, who was later discovered to have been absent from the scene of the skirmish was discharged unconditionally after the proceedings.
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"In all, the three policemen will be posted out of Rivers State to other Commands and Formations to continue their police duties," Mr Adejobi said.
"The Inspector General of Police has therefore tasked officers and men of the Force to be diligent and uphold the lofty tenets of professional policing in the discharge of their duties with respect for the fundamental rights of all citizens in line with the provisions of the 1999 Constitution of the Federal Republic of Nigeria (as amended)," he added.
The Rivers incident occurred a few days after a police officer allegedly shot dead a young man in the neighbouring Delta State for reportedly refusing to give N100 bribe.
PREMIUM TIMES reported how youths in Delta State protested with the victim's corpse along major roads in Asaba.
The victim, Onyeka Ibe, was inside a car with his wife when he was shot.
The officer who allegedly shot the man had been arrested and detained.
