A young Kurdish man died from a fire in a German prison after being wrongfully detained.
Amed was from Afrin, northern Syria, and accused of committing sexual harassment.
German police mistook him for Amedy G, a man from Mali who was wanted by police for a robbery in Hamburg.
The death of Ahmed has drawn attention in the German state of North Rhine-Westphalia.
The public prosecutor in the city of Cleves said multiple authorities now are involved in the case
"We are now launching an investigation against six policemen... We are now keen to find out who has made the mistake and where the issue initially started leading to the wrongful arrest," said Senior Public Prosecutor Gunter G. Naifer.
The interior ministry has apologized to the family of the victim.
Sonja Bongers, a member of the state parliament, described the incident as a 'judicial scandal' for Germany.