Thousands of people rallied in Burkina Faso’s capital, Ouagadougou, on Wednesday to demand an end to impunity and mark the death of journalist Norbert Zongo, whose murder eight years ago led to constitutional changes that were supposed to improve human rights in the country.

“We denounce the [ongoing] extrajudicial killings and we demand that the government undertakes speedy reforms of the judiciary system to try all criminals and their protectors," Tole Sagnon, vice president of the Coalition Against Impunity, told IRIN.

The coalition, made up of political parties, civil society groups and human rights organisations, was formed after Zongo's death to push for a transparent investigation and the arrests of his killers. His murder triggered unprecedented street protests in Burkina Faso, a former French colony with a history of military rule and a mixed record on free and fair elections.

Zongo was found dead in his burned out car on 13 December, 1998, in the midst of his investigation into a murder case involving the chauffeur of President Blaise Compaore’s younger brother.

Last July prosecutors drop the case of Marcel Kafando, the former head of presidential security and the only suspect in Zongo's killing, on grounds that the main witness failed to recount details of his meeting with Kafando hours before the crime.

"Our message is to tell authorities that we won't accept the dismissal of this case and that we are asking for it to be reopened," Sagnon said.

The Burkina Faso Human and Peoples Rights Movement (MBDHP) has pointed to the October killings of three businessmen, including a gold trader, from the eastern town of Piela as the most recent example of the country’s prevailing climate of impunity.

“We shouldn't be talking about this today because it should have been stopped by now,” MBDHP secretary general Chryzogone Zougmore told IRIN. “Despite our protests, the practice continues.”

Police detained the three men on suspicion of banditry and five hours later they had been shot dead.

Yarga Larba, an influential member of the ruling party and a former defence minister, has lodged a protest against the killings. He and three other parliamentarians, all from the east where the killings occurred, have called for an independent investigation. They accuse local police officials of involvement in the murders and have called for their suspension pending an investigation.

Larba alleges that the killings were premeditated. About 6.5 million CFA (US $13,000) and 3.5 kg of gold were allegedly taken from the home of the gold trader. Larba has also accused the local police chief of trying to conceal debts he owed the businessman.

The recent killings were the latest in a series of extrajudicial killings, human rights groups say.

Police allegedly executed four factory workers on the outskirts of Ouagadougou last December on suspicion of banditry. In 2002, the MBDHP said it had uncovered the bodies of 106 people killed execution-style and abandoned in various parts of the country.

The government promised to investigate but no progress has been made, rights groups say.