PORT-AU-PRINCE, Haiti — The three friends had spent the day stocking up on food in the Haitian capital when they left for their village, setting off on the 20-mile trip home on foot because the minibuses known as tap-taps weren’t running after a bridge collapsed.

Their bodies were found the next morning in a ditch along the way. They had been beaten, stabbed and burned, and relatives who identified them in a morgue said their tongues were cut out in an apparent act of ritualistic savagery.

The women’s families and friends suspect they were targeted because they were deaf in a country where experts say a pervasive stigma isolates people with disabilities such as deafness and can spark superstitions leading to horrific cruelty. Disabled women and girls are particularly vulnerable.

Due to cultural prejudices and the weakness of the justice system, past crimes against disabled citizens have been largely ignored. But the slayings of Jesula Gelin, Vanessa Previl and Monique Vincent have galvanised Haitians with disabilities and prompted rare public protests by their advocacy groups.

Outrage is particularly acute in the village of Leveque, where the women lived in a community of 168 homes established by US religious organisations for deaf people displaced by the 2010 earthquake. Gelin’s husband, Micheler Castor, now struggles there to raise their six kids alone.

“I can’t understand it,” Castor, also deaf, said in sign language of his 29-year-old wife’s killing. “She served the Lord and was a good wife and mother.”

Advocates for the disabled in Haiti say they hope what happened can chip away at the obstacles to justice and social inclusion faced by these most vulnerable citizens of the hemisphere’s poorest nation.

Around the globe, treatment of the disabled varies widely from country to country, but discrimination and barriers to inclusion are commonplace. Those problems are most severe in the developing world, where the World Health Organisation says 80 per cent of disabled people live.

“This case is very important. The disabled have made advances in Haiti, but there’s still far, far too much stigma and impunity,” Michel Pean, a blind activist who was Haiti’s first secretary of state for the integration of disabled people.

With pressure from that government agency, police have arrested three members of a family suspected of murdering the deaf women. Investigators say two women and a man are in custody, while the two men who are the main suspects are still being sought.

“We won’t rest until we get them all,” said Jentullon Joel, police commander in Cabaret, where the women were butchered in a cinderblock house off the main road.

The three women often prayed together, sold rice and popcorn in their community and regularly went to Port-au-Prince to buy supplies. Gelin and her two unmarried neighbors, both in their 20s, might have stayed overnight in the capital if they had known the bridge was out. But as darkness fell, they tried walking home instead.

Neighbours around the Cabaret property where they were killed said they didn’t hear any commotion that night.

Associated Press journalists found the house locked from the outside, a skinny dog growling in the yard.

Joel said one suspect told investigators that the deaf women were killed by her husband because the family feared that they were werewolf-type creatures called “lougawou”, their disabilities the product of a hex.

Nicole Phillips, a human rights lawyer representing the victims’ families, said the trio only felt safe approaching the house in Cabaret that night because one of the deaf women was apparently a distant relation of a person who lived there.

There’s another suspected superstitious motive that detectives are investigating. Some soothsayers claim they can mystically increase chances at winning bets at ubiquitous Haitian lotteries if they are brought body parts like tongues from fresh corpses.

“I believe they picked them to cut their tongues to play the lottery,” Castor signed in his tiny home, shaking his head beneath a poster of the Ten Commandments and holding a well-worn family photo showing his wife.

Whatever the motive, the killings have left many shocked and shamed in Haiti, where advocates estimate that roughly 10 per cent of the population, or about one million people, have some disability.