Mtobi Namigambo had gone to work for the day when his then 3-month-old son, May Mosi, was attacked.

"I had gone to the lake to fish. They were all alone in the house when the attackers struck," Namigambo told BBC. "My wife jumped out of the window and ran to safety with May, leaving the two children behind, who were not harmed at all."

"After jumping out of the window, they still came after me and I was screaming for help," Namigambo's wife, Sabina, said. "They only backed off when I woke up the neighbors."

Namigambo lives on Ukerewe Island, which used to be a sanctuary for albinos. His four-year-old son, May Mosi, has albinism.

People with albinism lack pigment in their skin and appear pale. In Tanzania, they are killed "like animals" and their body parts are used in potions believed to bring wealth and luck. Over 70 albinos have been murdered in the last three years, but there have been only 10 convictions, campaigners tell BBC.

Alfred Kapole, chairman of the regional Tanzania Albinism Society, had to escape to Mwanza city when a village leader tried to kill him for his hair. Another attempt on his life was made this year, according to BBC.

"He was among the first person with albinism whose case reached the courts," Vicky Ntetema, head of Under the Same Sun, told BBC.

In May of this year, a woman with albinism was "hacked to death," according to the BBC.

"We would urge the government to do more in educating the community here," Namigambo told BBC. "The government once held seminars about albinism. It made a lot of difference, but not anymore."

A campaign has been launched by the Tanzania government to urge communities to stop targeting albinos, but the biggest threat comes from rural areas, where television and radio has no reach.

Mashaka Benedict, a representative of the Sengerema Albino Society, told the BBC that it is the educated, wealthy businessmen and politicians that seek out the body parts of albinos. Benedict believes that is why the arrest and conviction numbers are so low.

"How can a poor man offer $10,000 [£6,300] for a body part? It's the businessmen and politicians who are involved," he told BBC.

The police say they are doing their best. "These cases are complicated because most incidents happen in very remote areas where there is no electricity, for example, and that makes identifying perpetrators at night very hard," Mwanza police commander Valentino Mlowola told BBC.