The chief of police in the Democratic Republic of Congo has been suspended in an investigation into the death of leading human rights campaigner Floribert Chebeya.

Interior Minister Adolphe Lumanu also confirmed that several officers were arrested in the investigation.

Reading out a communique on national television, Mr Lumanu said President Joseph Kabila was 'determined that all light be shed' on Floribert Chebeya's murder.

The minister said 'to allow the inquiry to be conducted smoothly' the national defence council decided as a precaution to suspend inspector general John Numbi at an extraordinary meeting last night.

'Preliminary elements of the inquiry resulted in the questioning and arrest of certain police officers,' he added.

The 47-year-old head of the group Voix des Sans-Voix (VSV - Voice of the Voiceless) was found dead on Wednesday, tied up in the back seat of his car on a road to the west of the capital Kinshasa.

He went missing with his driver, who has still not been found, late on Tuesday.

According to VSV, he had been due to have a meeting with the police chief at police headquarters.

John Numbi, 48, is a close ally of the president, who appointed him police chief in June 2007.

More than 50 human rights groups, including Amnesty International and Human Rights Watch, have demanded an independent inquiry into the killing in an open letter to President Kabila.

Calls for an independent investigation also came yesterday from rights groups in Brazzaville in the neighbouring Republic of Congo, and on Friday from the US, the EU and the UN.