A human rights group has urged authorities in Mozambique to investigate the alleged use of tear gas by police forces during a funeral of a popular rapper known for his critical stance against the government.

Edson da Luz, known as Azagaia, died last week due to a sudden illness, and his death prompted vigils across Angola and Mozambique. In a new report on Thursday, Human Rights Watch (HRW) said the police dispersed his supporters using tear gas during his funeral on Tuesday.

It urged the government to probe the incident.

The funeral was held with thousands of people joining the convoy carrying the coffin to the cemetery. Songs of the late singer could be heard in the main streets of Maputo, the country’s capital, as a tribute to Azagaia.

Videos on social media showed the crowd singing Vampiros (Vampires), a song that compares corrupt leaders to vampires.

As people were approaching the president’s official residence – an area off limits to pedestrians – the police fired tear gas on mourners without warning after ordering the crowd to change their route, HRW said in the report.

The report also said heavily armed riot policemen and three armoured vehicles were deployed to block the crowd.

HRW collected accounts of several witnesses and monitored the event via social and local media and saw the use of tear gas.

“We wanted to take the coffin to Michafutene [cemetery] and they [the police] never told us why we couldn’t,” a 22-year-old man told HRW. “Instead, they were nervously screaming at us and showing us their guns.”

A 26-year-old woman said, “I left my house to pay homage to Azagaia, not to fight with police. We didn’t have any guns; they had many guns and tear gas.”

According to United Nations guidelines on the use of less lethal weapons to enforce the law, tear gas should not be used to disperse non-violent demonstrations.

HRW called for a probe.

“Mozambique police responsible for safety and security at funeral processions or other public gatherings should always abide by human rights standards for the use of force,” said Ashwanee Budoo-Scholtz, deputy Africa director at HRW.

“An impartial investigation is needed to determine whether officials unnecessarily rushed to use tear gas and to hold them accountable,” she said.