welcome to "the lead." i'm jake tapper. we begin with our national lead. what was supposed to be a fun night at a bar ending in tragedy and disaster. at least 12 people have been killed after a gunman opened fire at a california bar last night. it was college night with people dancing, playing pool, hanging out with friends. police say the shooter was a 28-year-old white man, and they add they had been called to his home before. that's his home where he lived with his mother. they were called there because of a domestic disturbance. a neighbor telling cnn that the shooter's mother lived in fear of her son. authorities still do not know the motive behind the attack. it's a scene that has become all too common in the country. it's the worst mass shooting in 11 days, disturbingly cnn was told by at least one survivor of the shooting last night he was also a survivor of the shooting at las vegas at the route 91 harvest festival just over a year ago. more from outside the shooter's house in newbury park,