He said the suspect confessed to the crime.
The police spokesman said a 45-year-old man, Ibrahim Tijani, was fatally wounded by the elephant. A local, Muhammadu Bingin, was reported missing after the elephant attack.
Mr Edafe said the suspect was arrested on Saturday in his hideout in neighbouring Anambra.
The police spokesperson, Bright Edafe, said the suspect sold the baby after lying to her boyfriend that the child had died and had been buried.
The CP urged community leaders in the metropolis to sensitise residents to the dangers in using fire crackers.
