Human Rights Watch has condemned what it says is a “disturbing silence” in Rwanda over the murder of an anti-corruption activist six months ago, accusing police in the central African nation of foot-dragging.

Gustave Makonene, a local co-ordinator for the international graft watchdog Transparency International whose work included documenting allegations of police corruption, was found murdered in July last year.

Human Rights Watch said four arrests were made after the murder, but the suspects were released due to lack of evidence. The group said that since then, investigations “appear to have stalled”.

“In most other countries, the unresolved murder of an anti-corruption campaigner would have made the headlines, and independent groups would be clamouring for justice,” Daniel Bekele, Africa director at Human Rights Watch, said in a statement released on Wednesday.

“Instead, it seems everyone is just hoping the issue will go away. This sends a chilling message to those campaigning for accountability in Rwanda.”

Contacted by AFP on Thursday, a spokesman for the prosecution office insisted that investigations were ongoing.

“The investigation continues. We are continuing to follow all possible leads,” Alain Mukuralinda said.

Human Rights Watch said its own investigation into the killing had revealed that the victim was apparently tracked by a police officer in the days leading up to his death.

“The fact that Makonene may have been looking into police corruption and that a police officer was seeking to confirm his identity just before his murder raises questions, at the very least,” Bekele said.

The rights group added that the silence over the case “illustrates the weakness of independent organisations and media in Rwanda” caused by what it alleged were “years of government intimidation, threats, and infiltration”.