Ibrahim Umar, leader of a gang of suspected kidnappers, has reportedly confessed drinking blood of victims who cannot afford ransom.
Umar is among 16 suspected kidnappers who were arrested in Niger state.
They were accused of "terrorising" people along the Abuja-Kaduna road in Sabon Wuse in Tafa local government area of Niger state.
Addressing reporters at Sabon Wise on Tuesday, Jimoh Moshood, force spokesman, said items recovered from the suspects were five AK 47 rifles, nine AK 47 magazines, two cutlasses, one cell phone and 1,598 rounds of ammunition.
He said the arrest followed coordinated operations by the special tactical squad operating in the area.
The spokesman said that the gang leader confessed to killing at least 10 persons.
Moshood, who said that the suspects were arrested during the Yuletide, said it was a huge success for the police and Nigerians.
He said the suspects have all confessed to the various roles they played in the commission of the crime.
"The suspects will be arraigned in court after the completion of investigation," he said.
He said the force had evolved a new security arrangement to fight and prevent crimes in the country.