And Rebecca as we try to make sense of something that seems so senseless. We're learning more about the man police say is responsible. Corey Cobb Bay's posts online show a history of tense interactions with police and his father tells me his family noticed a change in his behavior in the past few days. The sound of the gunfire and the bullet holes it left behind. Do not answer why. But now we know more about who sources say it was 30 year old Corey Cobb Bay who ambushed and killed a Dallas police officer and shot two others just hours before the shooting, he posted video to Facebook of a drone and said the people flying it want to destroy the world. Is there any problem in another video? This month, Cobb approaches and questions police officers in an unmarked SUV. He claims someone is following him in another. You see like these demons. I'm telling you man on his Facebook page, I heard that he's talking about like demons or something like that. Emery Cobb says his son started acting strangely a few days ago. I feel like somebody was chasing him like the police was after doorbell. Camera video shows the SWAT team pull up to his house around 2 a.m. police force. Emery Cobb says they busted in the window of the backyard guest house where his son lived and took his son's laptop and magazines from his gun. He was a very good to me. Basically, he says Corey lost his job as a trucker earlier this month and may have used laced drugs. He says their family is struggling to understand how his youngest son could kill a cop. Unbelievable. You know, we uh I could, I couldn't believe it myself because he never behaved anything like that in Dallas. I'm Cole Sullivan. And right around the time that his son was shot and killed in Lewisville, paramedics were taking the wounded officers to hospitals nearby Officer Burkes was rushed to Methodist hospital around 1 a.m. and you could feel the weight of emotion from dozens of family friends and coworkers as they gathered outside hugging one another. His close family was slowly ex escorted in to say their final goodbyes. And almost immediately we saw officers converging outside Baylor Scott and White. That is where first responders took senior corporal Jamie Farmer and Carissa David. Officer farmer was treated for his gunshot wound and released this afternoon. But officer David is still in critical condition right now.