STEPHENVILLE, Texas (CNN) -- Incoherent. Talking nonsense. Erratic. Not the man they knew.
That's how family members and friends have described Eddie Ray Routh, the man on trial for the slayings of Chris Kyle, subject of the hit film "American Sniper," and Kyle's friend, Chad Littlefield, at a Texas firing range two years ago.
No one disputes that Routh shot and killed the two men. But defense attorneys say Routh was insane.
On Wednesday, the suspect's sister, brother-in-law and former girlfriend testified about Routh's behavior before and after the killings.
"I asked him if he was seeing things, and he said yes," Jennifer Weed, his ex, told the court, describing a conversation that happened the night before the slayings. "And then I asked him if he was hearing things, and he said yes."
Weed testified that Routh got out a yellow legal pad and started writing.
"And when I tried to speak to him he would take his hand and cover my mouth because he didn¹t want them to hear what I had to say," she said.
Routh's demeanor after the killings was equally strange.
"He said he had to take two souls before they could take his. And I asked him what he meant by that, and he said they were out to get him," Laura Blevins, his sister, told the court. "He was talking nonsense."
She said she told him: "I love you, but I hate your demons."
"The man who was my brother was not at my house. The person who came to my house is not the man who I knew was my brother," Blevins testified.
Her husband said that Routh "babbled about other incoherent things."
"I had a sick feeling on what it meant," Gaines Blevins told the court.
Prosecutors have described Routh as a troubled young man, but they argue he wasn't insane; they say these are the actions of a cold-blooded killer.
'I don't know if I'm insane or sane'
On Tuesday, prosecutors showed a video of police placing Routh into a squad car moments after authorities chased him down a Texas highway.
In the video, Routh is breathing heavily and teary-eyed.
An officer asks if he's OK. Routh replies: "I'm just so nervous about what's been happening in my life today. I don't know what's been happening. I've been so paranoid schizophrenic all day. I don't know what to even think of the world right now. I don't know if I'm insane or sane."
The small arsenal of weapons Kyle brought to the range that day was shown to the jury, which included five long rifles and several handguns, including one of Kyle's rifles labeled "American Sniper."
According to defense attorneys, Routh, in his psychotic state, thought he was walking into a showdown on the range.
Mother cites mental health problems
Taking the stand for the defense, mother Jodi Routh described her son's history of mental health problems.
After his time serving in the military, she said, "he was no longer his happy-go-lucky self."
His first stay in a VA mental ward was for three days in 2011, she said. Then he returned again, against his will, and spent weeks in the facility. When he was released, she said, he was on nine medications, including mood elevators, anti-psychotic medications and sleep aids.
Jodi Routh said she had asked Kyle to help, telling him that her son had been diagnosed with post-traumatic stress disorder.
She told Kyle that her son had been hospitalized multiple times, but did not tell him that he'd also threatened to kill himself and his family.
"Do you regret not sharing that level of detail?" prosecutor Jane Starnes asked.
"I just wanted to get help for my son," the mother replied.
Routh's trial comes just weeks after the release of the film about Kyle, a former Navy SEAL who claimed to be the deadliest sniper in U.S. history, with 160 confirmed kills in Iraq. "American Sniper," directed by Clint Eastwood and starring Bradley Cooper, has grossed the most ever for a war movie.
Kyle's autobiography by the same name spent weeks on best-seller lists. He had already risen to fame through his book when he died and was involved in charitable work to help former troops suffering from post-traumatic stress disorder.
Kyle and Littlefield took Routh to the firing range as a kind of therapy.
The range is a small, remote part of the sprawling 11,000-acre Rough Creek Lodge, and the men were isolated.
A hunting guide found Kyle, 38, and Littlefield, 35, who also was a veteran, motionless and called 911. The men were dead when officers arrived.
CNN's Catherine E. Shoichet and Dana Ford contributed to this report.