The NLC accused the police and Governor Uzodinma of Imo of being responsible for the assault on its president.
The Inspector General of Police, Kayode Egbetokun (IGP) has ordered investigation into the alleged assault on Joe Ajaero, the president of the Nigeria Labour Congress (NLC).
The Force spokesperson, Olumuyiwa Adejobi, disclosed this in a statement on Friday.
Background
There was an uproar in the state on 1 November when some thugs and police officers reportedly attacked Mr Ajaero and other members of the NLC who had assembled at the union's council secretariat ahead of a planned protest against the state government.
The national leadership of the NLC later alleged that Mr Ajaero was arrested by police operatives in the state.
The union also accused the Imo State Governor, Hope Uzodinma, of mobilising the thugs and the officers to attack the NLC president to frustrate the planned protest in the state.
But the police later denied arresting Mr Ajaero, saying they only placed him in protective custody to shield him from attack by the thugs.
On his part, Governor Uzodinma, who is seeking reelection in Saturday's election, blamed Mr Ajaero for his alleged partisanship in the state.
"What has happened in this ugly coincidence is that the national president of the Nigeria Labour Congress is from Imo state and has not been able to demarcate the difference between being a national leader of an organisation and then an interested party in local politics," Mr Uzodinma said at the presidential villa on Thursday in Abuja after receiving the flag of his party, the All Progressives Congress, from President Bola Tinubu.
The NLC, last Tuesday, declared an indefinite strike to protest the alleged assault on its president.
Investigation
Mr Adejobi, an assistant commissioner of police, said in the statement, that the IGP has now directed the deputy inspector general of police in charge of the Force Criminal Investigation Department to take over the case to ascertain the "true facts" about the alleged assault.
The force spokesperson added that the IGP has instructed the deputy inspector general of police to "address any ambiguities" in the matter, given that that the police have been inundated with different versions of the incident.
"The Nigeria Police Force understands the importance of transparency and accountability in maintaining public trust. The IGP therefore assures the public, most especially the leadership of the organised labour, that a thorough and unbiased inquiry will be conducted to provide clarifications while urging organised labour and the public to remain calm, as he has personally intervened to address the issues surrounding this incident," he said.
"The investigation has commenced, and the Nigeria Police Force guarantees that it will be followed to a conclusive end, and appropriate actions will be taken based on the findings of the investigation," Mr Adejobi added.