Two people suffered injuries described as not life-threatening when they were shot Tuesday afternoon in Roxbury, police said. Cruisers arrived at the intersection of Martin Luther King Boulevard and Washington Street after a 911 call came in at 1:58 p.m., Officer Katherine Shea said. The victims were taken to Brigham and Women’s Hospital. Shea said the caller reported that a third person had also been shot, but police could not locate any other victims. The identity of the two people hospitalized was not immediately released. Detectives were investigating a possible motive.