Police say a man used the postal service to mail the remains of his friend's son from Rio de Janeiro to northeastern Brazil for reburial.
Police spokeswoman Morgana Cruz says postal workers in the state of Ceara detected the bones when they did an X-ray scan of the box containing them.
Cruz says an exhumation order was inside the box together with the bones that belonged to a 22-year-old man who died four years ago. She did not know how he died.
She says the young man's parents had asked their friend in Rio de Janeiro to send their son's remains for reburial in the city of Vicosa.
She said no one was arrested because neither the sender nor the receiver knew that it's illegal in Brazil to use the postal service to mail human remains.