The Haute-Garonne firefighters intervened around midnight on the Toulouse ring road, on the night of Friday 23 to Saturday 24 July.
They discovered the body of a man in his forties, below a bridge.
According to La Dépêche, the body showed signs of several stab wounds.
The prosecution entrusted the investigation to the territorial directorate of the judicial police.
For now, investigators are trying to understand if the man was "thrown" from a car or if he tried to flee his attackers after violence, above the expressway, on the banks of the canal. noon.
The police will be able to rely on the recordings of the video cameras of the expressway.
A knife was found there, which would confirm the thesis that the murder took place not far from where the body was found.