A police spokeswoman confirmed on Tuesday that the 46-year-old is being held on suspicion of murder.
The suspects, Christiana Ibanga and her boyfriend, Inyene Akpan, were apprehended for allegedly selling their own child for N450,000.
A 15-year-old was among the victims.
The fire broke out in a patient’s room in the hospital in Hemer, about 30 kilometres southeast of Dortmund.
She, however, added that detectives are on the trail of other suspects who had been identified by residents of the community.
Gunmen have kidnapped Ekpe Ogbu, the Benue commissioner for housing and urban development in Benue.
