with a murder trial starting today in Texas. A father charged with gunning down a drunk driver who hit and killed his two sons. And this morning we're hearing from his wife. Ryan Owens has that story.... See More
with a murder trial starting today in Texas. A father charged with gunning down a drunk driver who hit and killed his two sons. And this morning we're hearing from his wife. Ryan Owens has that story. Reporter: Cindy has lost two of her young sons and could lose her husband too if Texas prosecutors have their way. Half of my life is gone. Reporter: David is free now, but his murder trial starts this morning. The 32-year-old is accused of taking the law into his hands, executing the man who killed his 11 and 12-year-old sons right before his eyes. He was sitting there, trying to revive my son. Reporter: It happened late in 2012, south of house. David barraras ran out of gas and pushing the car down this street when an intoxicate indicated Jose Banda slammed into them, killing the boys. No lights in the rearview mirror. Next thing you know. Reporter: Prosecutors say the enraged father ran home, grabbed a gun and shot the 20-year-old in the head. Ban da's family set up a Facebook page demanding the killer go to prison. Whoever did it is getting away with murder. He deserves justice. Reporter: He said he never shot anybody. The defense claims there are no witnesses to the shooting. While there appears to be evidence beyond all doubt of motive, what's lacking is credible evidence to prove he's the one who pulled the trigger. What's more, the defendant dad has a lot of support in the community. There's even a Facebook page dedicated to freeing him. Trying to take my husband away from me after my kids being gone. Accusing him of something that he didn't do. I just don't think it's right. Reporter: For "Good morning America," Ryan Owens, ABC news, Dallas.
This transcript has been automatically generated and may not be 100% accurate.