KNOXVILLE, Tenn. (WVLT) -- His sisters and cousins maintain that the Letalvis Cobbins
convicted of Channon Christian's murder and rape is not the Letalvis Cobbins they love

"He's not a killer, he's not a killer," says sister Letressica "Misha" Davidson.

"It's not in my brother to kill anybody//

"If Talvis was involved, it must have been on something--not Talvis."
says cousin Lakeisha Young.

Young, Davidson and psychologist Dr. James Murray characterized Cobbins as the product of a drug-addicted mother who prostituted to
support her habit, and a father who was alcoholic, abusive and absent.

"Before she died, she blamed herself," Davidson says

"He's a nice man, but he has a quick temper," cousin Theresa Hullum says.

Murray told jurors that tests show Cobbins is of below-average intelligence, with a history of learning and behavioral problems, and school expulsions--whose only stabilizing force was a great aunt who died when he was 14.

Her death, Misha Davidson says, prompted their mother to force Cobbins to sell drugs.

"She told him if he didn't do it, wasn't gonna have nowhere to stay, nothing to eat," she says.

"But it was up to him--cause we didn't know where Marcus was at the time.

"Marcus" is Cobbins' older brother and co-defendant Lemaricus Davidson, whom prosecutors have alleged is the ringleader in the killings of Channon Christian and her boyfriend Christopher Newsom.

Family members claim Cobbins feared his brother, after years of being bullied and abused.

"He (Cobbins) wanted, I don't want to say--be like him (Lemaricus), but he didn't want to think he was a coward or punk," she says,

Under cross-examination from prosecutor Leland Price, defense-retained psychologist Dr. James Murray admits that Cobbins was able to stand up to his older brother on occasion -- most recently, over a carjacking near Memphis that sent the older Davidson to prison.

"Mr. Cobbins reaction was, 'I'm not gonna do that', Price asks.

"That's how it was reported to me, yes," Dr. Murray says.

Cobbins juvenile court record is sealed.

His adult record--in West Tennessee, Kentucky and New York -- recounts srelatively minor offenses before the Christian-Newsom carjackings, kidnappings, rapes and murders.

Family members insist that proves their point.

"I knew that if 'Talvis was involved, it was because of Marcus," Hullum says.

"I never thought that my brother would do anything like that," says sister Lekedria "Keke" Davidson.

"I couldn't think about him murdering someone."

Yet, Misha Davidson admits that Christian's and Newsom's killings were so savage, Cobbin's late mother backed off helping him hire a lawyer.

"She didn't want to get herself involved in it and not really know what happened."

Beyond his murder and rape convictions, Cobbins faces new charges leveled while in custody; of assaulting Knox County Corrections officers.

February 2, a guard alleges, Cobbins attacked him as he was being removed from his cell and pulled him to the ground.

July 24, another guard alleges Cobbins struck him with a drinking cup after refusing to go into lockdown.

Court clerks say Cobbins faces hearings on the "behind bars" charges next Monday.

Family members say Cobbins father lives close by, but he was not in court Tuesday to hear his son pronounced guilty,.

Nor Wednesday, to help make the case for sparing his life.