"The Paris prosecutor's office said that "an investigation to establish the causes of death" had been opened, noting that no suspect was found at the scene on Tuesday evening."
It's a mistranslation, the original quote is "Une enquête en recherche des causes de la mort est ouverte afin de déterminer l’origine du décès, aucun élément suspect n’ayant été découvert sur place par les services primo-intervenants. Les investigations sont en cours", which translates to "no suspicious element was found", not "no suspect was found"
Its a strange announcement.