[1][a] The initial investigation into Philippe's death concluded he had committed suicide via gunshot, following plans to carry out anarchist attacks against the French government and other high-profile individuals.

The case received significant media coverage, with French newspapers promoting Léon Daudet's claims of political assassination.

[2] When the sum of money was insufficient for the boat ride, Philippe returned to Paris under false name, meeting and receiving shelter from Georges Vidal, administrator of the anarchist newspaper Le Libertaire.

Another anarchist activist took Phillippe in during this time, stating that Daudet told stories, "typical of the exaggeration of adolescence", in particular "that his father beat him, punished him too severely, hated him, that he [Philippe] hated him and all the bourgeoisie he had fled, now that he wanted to take revenge on everyone by committing a dazzling crime", but Philippe did not receive any further aid in his planned attacks.

On November 25, the newspaper Le Petit Parisien ran a paragraph on Philippe's suicide, which was noticed by his mother, Mrs. Léon Daudet.

Georges Vidal gave an account of the circumstances of Philippe's disappearance, describing him as a "hero of anarchy"; criticizing Léon Daudet of having stiffeld the voice of his son.

[9] Also on December 4, Vidal wrote in a separate article that Germaine Berton, a French anarchist currently standing trial for the assassination Action française member and friend of Léon Daudet, Marius Plateau.

[11][12] Le Libertaire would publish a letter signed by eleven surrealists, including Louis Aragon stating "We are wholeheartedly with Germaine Berton and Philippe Daudet; we value every true act of revolt.

It stated, "The conviction of all our friends and mine, is that after having been lured – through his escape – into an ambush, chambered, suggested or coerced, and stripped of all his papers, Philippe was thrown to his death."

Léon would then claim that his son was killed as an act of "political revenge" and stated that it was "odious and imbecilic" to believe Philippe was an anarchist.

He concluded stated his was to carry out his own investigation into Philippe's death and was ready to begin filing voluntary manslaughter and misappropriation of a minor changes.

While the first inquiry did not name a specific suspect, the second filing claimed that Police Commissioner Colombo had carried out the execution, and three senior officials of the Sûreté Générale (including Controller General Lannes) and Le Flaouter conspired in the murder.

On July 30, 1925, the court, after examining Léon Daudet's arguments (six in total:[e] implausibility of suicide, contradictions of the cab driver, absence of bullet in the barrel of the gun, suspicious discovery of the cartridge case in the cab ten days after the tragedy, absence of trace of bullet in the cab, implausibilities contained in the account of the surveillance of November 24 in front of the bookstore Le Flaouter where ten experienced policemen let Philippe Daudet out of the bookstore) retained the thesis of suicide and issued an order of dismissal.

[18][19] Following the Court of Cassation dismissing his appeal, Daudet wrote numerous articles in L'Action française where he denounced and called for violence against the Sûreté générale, the taxi driver Bajot, Le Flaouter, and even the French government.