Word from the West Coast is that the field of prospective films about the Boston Marathon bombings just got a little less crowded. There had been three movies in the works: One called "Patriots Day," in which Mark Wahlberg was rumored to be playing former police commissioner Ed Davis; one based on "Boston Strong," the book by Casey Sherman and Dave Wedge; and another, "Stronger," based on the book by Jeff Bauman and starring Jake Gyllenhaal as Bauman, who lost his legs in the attack. But we're told Walhberg and CBS Films, producers of "Patriots Day," have purchased the rights to the "Boston Strong" project from 20th Century Fox for an undisclosed sum. Wahlberg will now play Boston Police Detective Danny Keeler, who's the lead character in "Boston Strong." (Keeler was in command at the finish line on Boylston Street and was instrumental in the hunt for the Tsarnaev brothers.) In addition to the feature films, directors Ricki Stern and Annie Sundberg are working on a documentary about the events of April 15, 2013, for HBO.