Who Killed Jean-Marie Leclair?

Who killed Jean-Marie Leclair? This is the question for an18th century murder mystery not yet definitively solved. Jean-Marie Leclair was one of the greatest Baroque Era violinists and composers living in France, when in 1764, he was found in the vestibule of his own home in a seedy part of Paris, stabbed to death. The culprit could have been his envious 40 year old nephew, Guillaume-François Vial, who wanted his uncle to promote his career before King Louis XV's court. Vial was a second rate violinist compared to his uncle. It could have been the ex-wife, Louise Roussel, who owned an engraving business and who made money out of Leclair's music compositions. It could have been a conspiracy between the two, nephew and ex-wife. Who knows for sure? Lieutenant Antoine-Gabriel de Sartine was frustrated in the police investigation. There simply was not enough evidence to arrest anybody!