Morin’s chief card was Commissaire Louis Grassien, sent from the Rheims police, who had formed a tiny anti-O.A.S. squad of ten trustworthy men. After weeks of patient work Grassien managed to sketch out an organnigramme of the O.A.S. — similar to that which Godard had composed of Yacef’s networks during the Battle of Algiers. He had managed to identify most of the O.A.S. leaders, but had proved incapable of tracking down a single one. Then, in September, a break came. An Italian ex-Legionnaire, “Pino”, turned informer and led Grassien to Godard’s hideout. That expert on underground techniques proved (as he always would) too elusive, but notes found in the raid revealed the name of one Maurice Gingembre, an important O.A.S. courier plying between Madrid, Paris and Algiers.

QUESTION: How did Grassien's organigramme approach compare in effectiveness to Godard's, and what made the O.A.S. so much harder to track down concretely?

Horne, Alistair, A Savage War of Peace- Alge…, loc. 1493