Santosh Nayak, resident of Lendhei village in Tarsingi area, was arrested yesterday by forest personnel, Divisional Forest Officer Ghumusar (North) K C Mishra said.
"The man confessed that he along with two others had laid the electric wires to kill wild boar," the DFO said.
The two other accused are still absconding, he said.
The 35-year-old female elephant and its calf were found electrocuted in Kanakhai jungle under Khallikote forest range on Saturday.