Jose Salvador Alvarenga, who survived 15 months on a boat in the Pacific Ocean, was suspected of cannibalism.
The Mexican's friend fell ill and died after 10 weeks of survival.
Relatives of the deceased claim that Alvarenga ate their loved one, writes the publication Lad Bible .
The Mexican's lawyer explained that the family of the deceased is thus seeking a percentage of royalties from the sales of a book written by the fisherman after the rescue.
He also added that the relatives' demand is pressure to obtain a share of the income from the fees.
Alvarenga said that he and his comrade immediately agreed not to eat each other's flesh in the event of death.
The Mexican also passed a lie detector test.
