NAIROBI, Kenya (AP) — Dozens of African civil society groups and press associations on Tuesday called for an independent investigation into the death of a Rwanda-based journalist, saying the official explanation lacked backing evidence.

Investigative journalist John Williams Ntwali had previously expressed fears for his life and told the Human Rights Watch rights organization that he had received phone threats and had strangers visiting his house.

His family was informed on Jan. 19 of his death, which Rwandan police attributed to a motorbike accident.

A joint statement by 90 organizations on Tuesday said that no evidence of the accident has yet been released.

“Rwandan authorities have failed to provide a police report, the exact location of the alleged accident, any photo or video evidence or detailed information on the others involved" in the accident, the statement said.

Ntwali has been described as Rwanda’s last independent journalist who exposed alleged human rights violations on detained opposition figures and journalists.

His latest coverage was highlighting the plight of people facing land evictions by the authorities.

United States Agency for International Development Administrator Samantha Power on Saturday urged the Rwandan government to independently investigate Ntwali's death.

Rwanda has in the past been accused of infringing on media freedom.