An increase in the number of attacks on people with albinism in Malawi since late 2014 by people seeking their body parts for witchcraft prompted Amnesty International to call on Tuesday for authorities to do more to punish those responsible.
The human rights group said April was the bloodiest month for attacks on albinos in the southern African nation, with four people murdered including a child aged under two. The child's father and four others have been arrested.
In the past 19 months authorities in Malawi have recorded the murders of 18 albinos and abduction of five others although Amnesty fears the real number is likely to be higher as many attacks in secretive rituals in rural areas are never reported.
"The unprecedented wave of brutal attacks against people with albinism has created a climate of terror for this vulnerable group and their families," Deprose Muchena, Amnesty International's director for southern Africa, said in a statement.
Senior government officials, including President Peter Mutharika, have publicly condemned the attacks and announced several measures, including the appointment of a legal counsel to assist with investigations, and a national response plan.
"However, these measures have failed to stop the violence," Amnesty said in its report published on Tuesday.
"Some perpetrators have been arrested, charged and convicted, but the majority of crimes remain unresolved. Charges and penalties often have not been commensurate with the gravity of the crimes, creating a sense of impunity," the report said.
At least 69 crimes against people with albinism have been documented in Malawi since November 2014, according to police reports.
Amnesty did not have figures for the number of attacks prior to November 2014, but campaigners, police authorities, families and community leaders all said the number of attacks had risen.
It is unclear what has triggered the surge, but mass unemployment and drought could be part of the reason, Simeon Mawanza, lead researcher of the Amnesty report, told the Thomson Reuters Foundation.
There is no systematic documentation of crimes against people with albinism in Malawi, where people with albinism number around 10,000 out of a population of around 16.5 million.
People with albinism face discrimination and threats, both at school and in their communities. Myths about albinism abound, including the belief that having sex with an albino is a cure for HIV.
"The images that you see, where they hack off their hands, their feet, it's so difficult to understand what goes on in such a mind to commit such a heinous crime against an innocent human being, merely because they look different," Mawanza said.
He added that children have been sold by their parents, and some of the attackers were close family members.
One woman told Amnesty researchers in Malawi: "Most people who attack (people with albinism) are close relatives ... I met one mother in Chitipa who was hiding her children out of fear. As a result, the children were not going to school."
Attacks against people with albinism have occurred elsewhere in southern and eastern Africa, including in Mozambique, South Africa, Tanzania and Burundi.
Last year, the United Nations warned of a surge in violence against albinos in Tanzania, Malawi and Burundi.
The Amnesty report came ahead of international albinism awareness day on June 13. Albinism is a congenital disorder affecting between one in 5,000 and one in 15,000 people in sub-Saharan Africa. It affects about one in 20,000 people in Europe and North America.