Joshua Stepp, who is accused of sexually assaulting and killing his 10-month-old stepdaughter, Cheyenne Yarley, took the stand just after noon in his own defense.
In 2009, the 28-year-old first told paramedics on the scene that his stepdaughter had choked on toilet paper and fallen off a couch.
His lawyer has said that was a lie told by Stepp, because he could not believe he killed the child in a fit of rage.
Tommy Manning told jurors Stepp "lost it" when he couldn't get the infant to stop crying at their apartment in south Raleigh where he also lived with his new wife and his toddler daughter from another relationship.
Stepp admitted pushing the child's face into the carpet creating a facial injury and causing head trauma.
He told the court Tuesday he put the child in the closet and became enraged when she continued to scream.
"The next thing I'm in the closet and I'm, I got her by the back of the head," Stepp testified. "I'm just rubbing her head into the carpet."
He told jurors the baby wouldn't stop screaming and was getting "inside my head."
"I don't know what I'm thinking," Stepp said. "I grab some toilet paper. I go run it under the sink, and I go back in the living room and I just, I put it in her mouth to try to get her to shut up. And I walk back into the kitchen, and I hear a cough and she starts gagging. I just knew, I was like, oh my God, I just messed, I just messed up."
Stepp said he tried to get the toilet paper out of Yarley's mouth, but she kept showing more signs of distress. At one point she appeared to die.
"She stops breathing and she looks at me, but she's not like looking at me," he continued. "She's like looking right through, and I look at her and that's just it. She stops."
However, Manning has said that his client could not remember much of what happened because the Iraq war veteran suffers from posttraumatic stress disorder and was self-medicating with alcohol and prescription pain killers.
The prosecution has worked to overcome that in part by asking their final witness - a former medical examiner who performed the autopsy on Yarley - whether the little girl was in pain during the beating.
"The most likely cause of death is abusive head trauma," former medical examiner Dr. Kevin Greene said. "If the child was coherent at that point when those injuries occurred then they would certainly have caused pain."
Greene said he suspected that trauma involved multiple blows to the head.
Prosecutors said there was also evidence that Stepp raped the child. But the defense has said the injuries to the girl's privates were caused when Stepp angrily cleaned her when she soiled two diapers after the assault.
Stepp denied the sexual abuse.
"No," he said. "God no."
Dr. Greene conceded on cross-examination that there was some validity to that theory.
"It is possible that fingers could have been used to create these injuries," he said. "I think two fingers is more plausible than a single finger even wrapped in a wipe."
But Greene later hedged some by pointing out that if there had been aggressive wiping, he likely would have seen redness and abrasions that weren't there.
Stepp's team hopes its claim that he suffers from PTSD will get the jury to spare him from the death penalty.
Stepp will be cross-examined Wednesday.