The boy Arshed went missing on December 3 and his body was recovered from the fields.
A 22-year-old man in Purba Bardhaman district took money from a neighbour's father pretending to be his son and killed the real son out of fear, police said on Wednesday.
"Jamal Sheikh of Babuidanga village has been arrested on Monday for killing his neighbour Arshed Sheikh, 14," a police officer of Purbasthali police station said.
The officer mentioned that the accused knew that the teenager had never seen his father, who lived and worked in Kerala and was separated from his wife years ago.
The boy lived with his maternal grandparents.
Police said that taking advantage of the situation, the accused collected the man's phone number, spoke to him as his son and asked for monetary help.
"The father had sent money to Sheikh but when the man expressed his desire to pay a visit, the culprit killed Arshed out of fear," said the officer.
Arshed went missing on December 3 and his body was recovered from the fields, the officer added.