After several years as a policeman in the Directorate of Territorial Security (DST),[1] Tillier pursued a career as a journalist, first writing for Minute, a right-wing weekly journal.
Using his past police connections and his friendship with Commissioner Lucien Aimé-Blanc, head of the Central Office For Combating Banditry [fr] (OCRB),[2] he began to write articles that contradicted the "honourable gangster" image conveyed by Jacques Mesrine, who in France was public enemy number one.
In spite of Mesrine's threats, Tillier continued to publish articles refuting the criminal's image as a modern day Robin Hood.
[citation needed] Tillier gained an exclusive interview with Mesrine on 10 September 1979, but Mesrine and his accomplice, Charlie Bauer [fr], drove Tillier to a candlelit cave in the Forest of Halatte, where they forced him to strip naked before handcuffing him.
In his editorial published on 9 February 2008, entitled "On s'en tamponne mister Président", he announced his departure from the JIR.