Murder six students. on the evening of april 30th. a friend of would-be gunman calls a mental health center. then, he calls 911. at some point deputies are told about the reported disturbing videos he posted online. they arrive for a welfare check at the 22-year-old's apartment. >> authorities contacted him directly at his residence. and they determined he didn't meet the criteria for voluntary mental health hold. >> reporter: officers spoke to him about his videos. he said that they were just a way to express himself. he wasn't fitting in socially in isla vista. they did not enter the apartme...