Efraim Diveroli is suing Cooper, 41, who is a producer on the film, Phillips and executives at Warner Bros, claiming they had unauthorised access to his "Once a Gunrunner" manuscript and could have used elements from it in the film, reported Contactmusic.
The movie centres on a pair of drug users who become arms dealers after they win a hefty amount contract to supply American allies with weapons in Afghanistan.
The screenplay is reportedly based on a 2011 Rolling Stone article and a subsequent book written by Guy Lawson, while Diveroli was in jail serving a four-year sentence after pleading guilty to one count of conspiracy.