PARIS (AFP) - Paris prosecutors have launched a judicial investigation for involuntary homicide following the Malaysia Airlines plane crash, a judicial source said Friday.

The probe was launched on Wednesday. Four French nationals were among the passengers, including three students from the French school in Beijing, and the mother of two of the pupils.

The aircraft disappeared on March 8 with 239 people on board and an intense search for the plane has been scaled back after coming up with nothing despite an air and sea hunt over 4.64 million square kilometres of the southern Indian Ocean.

The Malaysian government has been roundly criticised for the manner it responded to the crash and the way it conducted search operations.