Dr. Osahon was abducted last Friday at his residence at Odemwingie Street in Benin City.
Family sources said the kidnappers contacted the family on Saturday and demanded a ransom of N10 million.
The source said the ransom was later reduced to N4 million.
Meanwhile, colleagues of the abducted doctor took to the streets of Benin City on Monday, protesting the kidnapping.
They took their protest to the State Government House and called for the unconditional release of their colleague.