Drake announced the decision Thursday, saying an investigation by the Bartlesville Police Department determined that the April 7 death of Christopher Elijah Richardson, 31, was a justifiable homicide. The roommate grabbed a knife from the room after Richardson refused to stop the attack and stabbed Richardson three times, Drake said. "Richardson was committing a forcible felony at the time [the roommate] intervened," Drake said in a statement. "[The roommate] was justified in using deadly force in this situation to stop or prevent this type of felony and prevent the serious injury to or possible death of [the other individual]." The district attorney called the case "a tragic situation" and offered condolences to Richardson's family.