It was the first full day of testimony from witnesses called by defense attorneys for Eddie Ray Routh.
Routh's use of marijuana and alcohol and his temperament was a constant theme throughout the morning.
Routh's ex-girlfriend, Jennifer Weed, said she met Routh online in spring 2012.The two briefly lived together before only spending the nights on weekends.
Weed said Routh's use of marijuana became an issue in 2013 and he told her he was seeing things.
The night before the shooting, Routh proposed to Weed and she responded yes. Routh had asked previously, but Weed said it was when he was in the VA hospital and she wouldn't agree to the marriage until he was allowed to have shoelaces.
Weed also said two weeks before the killings, Routh wouldn't let her or her roommate leave their apartment. She said he grabbed a sword and knife, saying he was trying to protect them.
Routh's sister, Laura Blevins, told the court she loved her brother, but hated his demons.
Routh went to her home after he killed the two men and confessed to the crime, but at first, she didn't believe him. Then she saw an unfamiliar truck outside and realized he might be telling the truth.
Blevins said he appeared "out of it" and "in a daze" that afternoon.
Defense attorneys have said Routh, a former Marine who was taking anti-psychotic medication, was insane when Kyle and Littlefield took him to a shooting range to provide support and camaraderie.
They're trying to convince jurors to find Routh not guilty by reason of insanity. Prosecutors say he knew his actions were wrong and should be convicted of capital murder.