Maurice Landstrass was the proprietor of a dry cleaning store and was in the employ of Navi Araz at the start of Day 4. He was hired to use his store to shelter high-level terrorist Tomas Sherek from the authorities. Maurice was nervous when questioned by Ronnie Lobell from CTU, and his behavior, with the help of Jack Bauer who had been watching Lobell/Landstrass from a camera, blew Sherek's cover. Jack noticed that Maurice was looking at a direction Sherek likely was; after hearing Jack's advice, Ronnie shoved past Maurice and apprehended Sherek.
It was not established if Maurice had knowledge of Sherek's crimes and ultimately Habib Marwan's terror plot. It was not shown on-screen if he was apprehended for his role as an accessory to terrorism and harboring a fugitive.