The dead man was 35 year-old Mbame Ndiaye, a Senegalese who had lived in Spain for 14 years yet failed to ever gain citizenship.

By Aritz Parra and Iain Sullivan 

The death, and the clashes between riot police and protesters that followed late Thursday in a central Madrid neighborhood, cast a spotlight on the precarious situation of a large community of undocumented migrants.

Madrid Mayor Manuela Carmena on Friday announced a “thorough investigation” into the death of the man. According to city officials, he was treated for a cardiorespiratory arrest that took place an unspecified time after he escaped a police crackdown on informal street sales on Thursday.

Subsequent protests by hundreds of African migrants degenerated into rioting. Demonstrators burned plastic trash cans, blocking narrow streets and setting fire to a bank branch. An Associated Press reporter saw protesters throw rocks at dozens of riot police officers.

Police said six people were arrested. According to the Madrid region’s emergency services, 20 people were treated for minor injuries, including 16 police officers.

Migrants’ associations have identified the dead man as 35 year-old Mbame Ndiaye, a Senegalese who had lived in Spain for 14 years and hadn’t been granted residency. They accused police of playing a role in his death, but local police unions said it had nothing to do with the crackdown on street vendors.

A police union representative said officers patrolling the area tried to help the man while medical help arrived