Mortar 'failure' caused deadly accident, says commander
                                
                                
                                    (Newser) -
                                    The Marine Corps has released the names of the  seven Marines accidentally killed  in a live-fire exercise in Nevada on Monday, reports the  Los Angeles Times . Eight people were also injured, one very seriously, although their identities have not been released. The victims were all based in Camp Lejeune, NC....