The remaining four staff of Osun College of Technology, Esa-Oke, who were kidnapped on their way from work on Tuesday, have regained their freedom, according to the police.
The police spokesperson in Osun, Folashade Odoro, confirmed their release to the News Agency of Nigeria (NAN) on Friday.
Mrs Odoro said that the abducted staff regained freedom in the early hours of Friday and had all been reunited with their families, but did not give details on the release.
"The remaining four abducted staff of the college have been released and have been reunited with their families.
"Efforts are still ongoing to arrest the gunmen that kidnapped them and the police will not stop until the perpetrators are brought to justice." she said.
The police spokesperson however did not say if ransom was paid for their release or not, but queried, "How can ransom be paid to abductors that were not seen?"
NAN recalls that suspected gunmen kidnapped eight staff of the college, and also killed one other who tried to resist being kidnapped.
The gunmen later freed four on Wednesday and there have been little or no details on how they regained their freedom.
The institution's spokesperson, Adewale Oyekanmi, had told NAN how the abduction took place.
He said that the institution's staff were attacked and kidnapped around 4:30 pm while leaving the college premises after close of work on Tuesday.
Mr Oyekanmi said the gunmen blocked the Esa-Oke Road leading to the college campus, stopped the staff vehicles plying the route and abducted them.
"One of the staff was shot and killed when he did not stop and was trying to escape in his car.
"The police, the DSS and men of the OPC are however helping in combing the bushes to see if they can rescue the kidnapped staff." he said