BRAZIL: The Brazilian authorities believe that hired death squads or "social cleansing" groups are the most likely perpetrators of attacks which have killed at least seven homeless people in Sao Paulo.
On one night alone five vagrants were clubbed to death as they lay sleeping in the central district near the cathedral, and another 10 were wounded.
Further attacks were carried out on subsequent days, despite an increase in police patrols. A seventh fatal beating was discovered on Thursday.
The police report that the victims were sleeping alone and, in most cases, were killed by a single blow to the head.
The murders, which have shocked social workers and human rights groups, highlight the plight of the estimated 10,000 homeless people living rough in South America's biggest city.
The mayor declared three days of mourning for the victims.
"The systematic nature of these crimes leave us in no doubt that this is the work of an organised group," Mr Pedro Montenegro, the ombudsman with the presidential human rights committee assigned to the case, said.
The police have not yet established a clear line of inquiry, but they have suggested that neo-Nazi groups may be responsible, pointing to the recent publication of pamphlets hostile to vagrants.
"This seems to be the work of a death squad, but the circumstances would suggest an isolated group acting with hatred rather than money as its motive," Mr Pedro Paulo Talin, co-ordinator of a group managing an anonymous tip-off service in co-operation with the police.
In another recent incident, six vagrants nearly died when they drank from a liquor bottle laced with rat poison.
The most notorious case of vigilante violence in Brazil was in 1993, when eight homeless children sleeping on the steps of the Candelaria cathedral in central Rio de Janeiro were killed.
Three off-duty policemen were eventually convicted, but the majority of the attackers escaped.
"It is our duty to ensure that this is not another case where the culture of impunity prevails, just because the victims are poor," Mr Montenegro said.
A church outreach group, Pastoral do Povo da Rua, reported a 25 per cent increase in the number of people using its shelters after the attacks, and called on the authorities to do more to protect the homeless.