Duvalier -- also known as "Baby Doc" -- returned to Haiti Sunday after nearly 25 years of exile in France and AI was quick to speak out about his resurfacing.
"The widespread and systematic human rights violations committed in Haiti during Duvalier's rule amount to crimes against humanity," said Javier Zuniga, an adviser at Amnesty International. "Haiti is under the obligation to prosecute him and anyone else responsible for such crimes."
Duvalier, 59, took over for his father and ruled Haiti from 1971 until ousted in 1986. During his regime hundreds of people "disappeared" or were executed, AI said.
AI said members of Haiti's military and the militia National Security Volunteers played a primary role in repressing pro-democracy and human rights activists.
"The Haitian authorities must break the cycle of impunity that prevailed for decades in Haiti," Zuniga said. "Failing to bring to justice those responsible will only lead to further human rights abuses."
Duvalier kissed the ground after getting of an airplane Sunday when he arrived in Port-au-Prince.
"I've come to help," Duvalier told reporters.
Among those who greeted him were former officials of his regime, including Dr. Adrien Raymond, who was his foreign minister.