He was arrested after several women were found strangled in a similar way in different hotel rooms in Nigeria’s oil capital of Port Harcourt in Rivers state over the last month.
Rivers state police chief Mustapha Dandaura said the suspect had initially only admitted to killing five women, but after further interrogation admitted the number was 15.
“He took us to all the rooms he booked and killed those girls and he said he had killed nine [in Port Harcourt]."
The police chief said the man then admitted that he had murdered women in other places.
“He killed one in Lagos, one in Owerri, one in Sapele, one in Aba, one in Benin and one in Ibadan so now we have 15,” he said.
The man had been prompted to confess after officers elsewhere, recognising similarities with cases they were investigating, got in touch with the Port Harcourt investigators.
“Two CID [Criminal Investigation Department] women came from Aba [on Monday] with the picture of a woman he killed the same way he killed others, tied her hands and legs," the police commissioner said.
“The CCTV camera captured him with the same dress he’s wearing, so I said they should go and interrogate him. Immediately they saw him, they said that he was the one - and he didn’t deny it.”
The police have been under pressure to stop the killings following a social media campaign using the hashtags #ProtectPHWomen and #ProtectPhGirls.
Last Wednesday, more than 70 women's groups marched through Port Harcourt demanding the police do more to make the city safer for women.
In response, Mr Dandaura set up a special task force to improve security at hotels, saying any that did not comply with new guidelines, which included installing CCTV cameras and asking guests for documentation when registering, would be closed down.