'Police and justice officials now require support if they are to fully investigate the claims against Amio Metayer and determine the truthfulness of the allegations against him,' the organisation said.

Supporters of Amio Metayer have been staging violent demonstrations throughout the week in Gonaives, and have threatened more violence if he is not released. In the course of this week's demonstrations, the Gonaives customs house was burned down and several people were reportedly injured in unclear circumstances. Amio Metayer has himself called for calm, and for an end to the violence. On Wednesday he was transferred to the Gonaives prison, and his case is under review by justice officials there.

'In addition to ensuring that the investigation into the allegations against Amio Metayer continues with full guarantees of due process, the Haitian authorities have the responsibility to investigate acts of violence committed by all parties in the days following his arrest and to bring those responsible to justice,' the organisation added. It reminded the Haitian National Police of its obligations to respect international codes of conduct regarding law enforcement in dealing with demonstrators.

The arrest of Amio Metayer followed the publication of a report on the 17 December attack and its aftermath by an investigative team of the Organisation of American States. The report had urged that all those implicated in the December violence be prosecuted without delay.