Effiong, who pleaded guilty in an interview with newsmen in Aba during his parade by the Abia Commissioner of Police, Mr. Leye Oyebade, said he beheaded the woman in the night and threw her head into the Aba River.
He said a spiritualist had advised him to perform the act as a sacrifice to avert an imminent danger of running mad.
Oyebade also paraded three final-year undergraduates of a tertiary institution, who admitted that they were members of a six-man gang which allegedly dispossessed somebody of a Toyota Highlander Jeep in Umuahia on October 10.
One of the suspects, Chimezie Chukwu, 24, told newsmen that the gang specialised in car-snatching and that the incident, which led to their arrest, was his third experience.
Besides the Highlander, a Mercedes Benz with registration number AG 467 NEM was also recovered from the suspects.
Other items recovered are one AK-47 rifle with two magazines containing 31 rounds of live ammunition and one locally-made revolver pistol with four rounds of live ammunition, among others.
Oyebade, who expressed concerns over the rising cases of crime and criminality in Abia involving undergraduates, restated the commitment of the command to check the phenomenon.