The woman, who was said to have resided at Apata Elere area of Ibadan, allegedly committed suicide by hanging.
The News Agency of Nigeria reports that the corpse of Oluwafemi, who was also known as Iya Iyanu, was discovered at about 8a.m.
A youth leader in the area, Mr. Ayodele Obaro, said the discovery was made by some auto-mechanics who had gone to the river bank to defecate.
“When I heard about the incident, I reported to the nearby St. Paul’s Anglican Church and the church later informed the police,” he said.
The younger sister of Oluwafemi, who simply identified herself as Iya Subomi, said the deceased was declared missing on Saturday when she left her son’s house without trace.
She added that the deceased was at her first son’s house at Odo-Ona on Friday before he left to attend a church vigil that night.
“However, by the time he came back on Saturday morning, her whereabouts could not be ascertained.
“Her disappearance was suspicious because she left the house without her shoes and phone,” she added.
She said news of the discovery of the corpse was conveyed to her on Monday morning.
“Her scrap business was thriving and her children are doing well.
“I am also very sure that she is not in debt, which keeps me in the dark over why she decided to take her life.
“She was strong-minded five years ago when her husband died and now that she had pushed through the difficult times, it will take God to say why she did this,” she said.
The Deputy Commissioner of Police in Oyo State, Mr. Clement Adoda, confirmed the incident in an interview with NAN.