KNOXVILLE, Tenn. (WVLT) -- Accused killer George Thomas called the murder of a Knox County couple "none of his business". It all happened during a taped jail phone call between Thomas and his girlfriend.

Thomas' trial began Tuesday. He's the third defendant facing a jury for the murders of Channon Christian and Christopher Newsom. He has pleaded not guilty to the more than three dozen charges. Prosecutors have no forensic evidence linking him to the crimes, but they say comments Thomas made to his girlfriend help show why he did nothing to stop the crimes.

"It's about criminal responsibility and it starts with that truck," said Assistant District Attorney Takisha Fitzgerald.

"That truck", prosecutors argued Tuesday, helped make Thomas criminally responsible for the murders of Christian and Newsom.

"It's the agreement in the front end with the truck." Fitzgerald said Thomas knew his co-defendants had planned a carjacking. She argued Thomas also hung around while the couple was killed.

Jurors heard Thomad defend himself in a taped jail phone call to his girlfriend:

"Why didn't somebody call the police and tell them this was going on? Cause, I mean, that girl didn't deserve the that she went through. Same with that boy," Thomas' girlfriend said in the call.

"Should've would've could've. But didn't, you know what I'm saying? It was none of my business in the first place," Thomas told her.

Defense attorney Thomas Dillard said his client never agreed to or participated in the carjacking, and Thomas kept out of the rapes and murders that followed.

"He is not guilty of these offenses," Dillard argued.

Dillard also called Thomas inaction reprehensible, but not criminal.

It's jurors, though, who will ultimately decide. Prosecutors also told the jury that Thomas said Christian, who he referred to as "that white girl", meant nothing to him. Police say Thomas made that comment after his taped interrogation ended.

Prosecutors say it's not about race. That's just how Thomas knew Christian.

The defense said that statement is not a confession, and it wasn't written down or reported to attorneys for nearly a year and a half.

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KNOXVILLE, Tenn. (WVLT) -- Opening statements are set to begin today, as George Thomas becomes the third of four defendants to stand trial for the January 2007 carjacking, kidnapping, rape and murder of Channon Christian, 21, and Christopher Newsom, 23.

You can watch the entire trial streaming live at VolunteerTV.com.

Get up-to-the-minute trial updates from Mike McCarthy by following @WVLT on Twitter.com.

2:40pm---Waste Connections worker Xavier Jenkins now on the stand. Jenkins saw Christian's SUV parked outside the Chipman Street house, where police believe Christian and Newsom were taken, then later killed.

2:00pm--An emotional moment comes after Channon Christian's dad, Gary Christian takes the stand. He took a long pause and testified , "She said I love You," talking about the last time he spoke to Channon by phone the night she disappeared. Gary also described the search for his daughter and moment they found her abandoned SUV.

1:40pm -- Sowards is identifying the clothing Channon Christian was wearing the night she was kidnapped. Past testimony has revealed the clothes were stained by Lemaricus Davidson's DNA and Letalvis Cobbin's DNA. None identified as belonging to George Thomas.

1:15pm-- Christian's friend Kara Sowards testifies about the night Channon didn't show up at a party as expected, as well as the later search and discovering of Christian's stolen SUV. Newsom's friend, Josh Anderson, has also testified about the events of that night.

12:00 pm--Court breaks for lunch. Back at 1:00pm.

11:00 am--Thomas' defenders say Thomas overheard Davidson and Cobbins planning to steal a car, but he didn't agree to it or participate. The defense said Thomas kept to his own business, and didn't know "they were going to steal the people in the car."

10:30 am -- Prosecutors continue opening arguments, telling jurors the timeline of the fatal crime spree. Prosecution says Thomas admits to being at Chipman street house and riding in Christian's stolen SUV.

10:00 am-- Opening arguments begin. Prosecutors tell jury Thomas knew his co-defendants were going to steal a car and was there when Lemaricus Davidson, Letalvis, and Eric Boyd got back with Christian and Newsom. Prosecutors will argue Thomas is criminally responsible for the crimes against the couple.

9:30 am-- George Thomas pleads not guilty to all 38 counts he faces, including first-degree murder.