COVINGTON, Ga. — Tara Robinson testified on the night of Oct. 8, 2017, while volunteering for a search party to locate a missing baby, she came upon something that didn’t look right.

Robinson found the hole were a drawstring athletic bag was concealed by a log and stick.

"The tree log was unusual to me, the way it was sitting. Under the log there was pile of sticks and twigs. I picked up one of the sticks and began to move away some of the leaves and that's when I saw the black string," she said. "I took the stick and pulled it up to see what it was, and it was a bag, and that's when I told one of the children to get the officer."

Newton County Sgt. Timothy Dickerson was the officer who would come over to the bag. Using his index finger and thumb on each hand, he carefully opened it to see what was inside.

“I could see clothing objects inside of it and when I was doing so, I kind of pulled on it and I could tell it had some weight to it,” he described.

Dickerson testified the bag could have possibly contained the body of 15-day-old Caliyah McNabb.

PREVIOUS: Her 2-week-old body was found in the woods near her home. Her parents are charged with murder.

The trial against her parents Christopher McNabb and Cortney Bell - accused of killing and covering up the murder of their 2-week-old baby - began Tuesday with opening statements and testimony.

McNabb and Bell are facing multiple charges, including murder, in connection with the crime.

In addition to allegedly killing their infant daughter, the two are also accused of then dumping her body in the woods, not far from the Eagle Point Trailer Park.

Melissa Davis, a neighbor who was called over moments after the baby went missing, said McNabb was "hysterical" and screaming, "They're gonna think I did this," while mother, Bell, was "hollering" the child's name over and over.

READ: 'They're gonna think I did this': Neighbor recounts alleged comments by murdered child's father

Davis described how she was called by Bell in the morning and then came over to their home.

"Chris was on the front porch. I went up to him, I said, 'Chris, calm down, what's going on?'" Davis recalled. "He kept screaming, 'They're gonna think I did this.' I told him to calm down, let's figure out what's going on."

"He said, 'the baby's gone.'"

Davis testified McNabb left the home, without anything in his hands, while Bell eventually called 911.

Newton County Sheriff’s Office Investigator Wade Freeman testified both parents gave multiple stories of who may have taken the child, such as McNabb’s father and a neighbor. However, both stories were quickly found to be untrue, as McNabb’s father was in Tennessee at the time and their neighbor’s home was searched by police.

Responding officer Joshua Hicks also spoke on the stand of how Bell exhibited a "sporadic," demeanor.

"She would be calm and collected as she'd begin describing what happened to the child, then she'd start to panic a little bit, then right back to being calm and collected," Hicks, a Newton County sheriff's deputy, said.

He also described how when McNabb, the father, returned from searching for the child in the woods, he was "fidgety."

"Like going in and out of his pockets, looking left, looking right," Hicks said.

The video showed Bell, appearing frantic and distraught, first meeting officers during their search in and around the home, and later showed their interaction with McNabb returning from the woods.

READ: Transcript of 911 call reporting little Caliyah McNabb missing

Bell appeared to have a black eye, still swollen - she did not explain how she got it. Her voice trembled as she said she couldn’t find Caliyah anywhere and had no idea who might have taken her.

It showed McNabb, too, returning from going into the woods around the home to immediately try to find the girl. Soaking wet from the rain, he told deputies he’d been searching for his daughter and also had no idea who might have taken her.

Another sheriff's deputy, Raymond Walden, was the first to encounter McNabb as he came back out of the woods. The deputy described their interaction on the witness stand.

"He was not excited or anything. He just walked up to me and looked at me. I noticed he was soaking wet, his feet was muddy, I said 'Where you been?'" Walden recounted.

"He said he left the trailer and went into the woods ... I said 'Why did you go in the woods looking for a two-week-old child?' He said, 'I was just looking.'"

MORE: Daddy's girl: How tumultuous past leads to heartbreaking ending

Bell's father Tim Bell testified earlier in the day, in one instance saying McNabb looked "shady" when he showed up from the woods, and indicating he felt the father used his children to get money.

Bell's cousin Megan Sorrels also testified, explaining how she often cared for Bell's children and had been concerned about their safety, when Bell and McNabb would fight or do drugs at home.

"She always had bruises on her," Sorrels said. "I've went through abuse myself, so I didn't really have to ask many questions. I could tell."

RELATED: Father, cousin testify in murder trial of parents accused of killing 15-day-old daughter

In opening statements, Newton County prosecutors told jurors they would hear that McNabb and Bell were negligent parents who created an unhealthy home for Caliyah and their 2-year-old daughter Clarissa, smoking meth and bringing drug-addicted friends into the house.

"We're not going to sugar coat anything for you, we're going to show you exactly how this baby was living," Newton County Assistant District Attorney Alex Stone said.

Defense attorneys countered that the state wouldn't be able to meet the burden of proving McNabb and Bell were responsible for Caliyah's death beyond a reasonable doubt.

McNabb's attorney Anthony Carter painted his client as a vulnerable father who was targeted by police simply because he was the easiest option.

"They focused like a laser on Christopher McNabb as being the person who killed his daughter," Carter said.

He said police "developed their whole case around supposition, the hypothesis that McNabb is one who killed his daughter."

Bell's attorney, Bryan Frost, said there was no evidence against his client.

"What I don't believe you're going to hear at all is any evidence whatsoever, direct or indirect, that my client had anything to do with this heinous crime against her daughter at all," he said.

The jury then heard the 911 call Bell made the day their daughter went missing, and McNabb wiped away tears.

A Georgia Bureau of Investigation medical examiner determined that the infant had died from blunt force trauma to the head.

McNabb was charged in October 2017 with felony murder, aggravated battery and concealing a death.

In January 2018, Bell was arrested and charged with second-degree murder, second-degree cruelty to children and contributing to the deprivation of a minor.

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