Police have not released a motive in the up-and-comer's murder
                                
                                
                                    (Newser) -
                                    Troubled rapper-singer XXXTentacion  was shot and killed Monday in Florida, authorities said. The 20-year-old rising star, whose real name is Jahseh Dwayne Onfroy, was pronounced dead Monday evening at a Fort Lauderdale-area hospital, the Broward Sheriff's Office said. He was shot earlier Monday outside a Deerfield Beach motorcycle...