Brooke "Skylar" Richardson faces several charges in the death of her baby

Brooke “Skylar” Richardson seemed to live a charmed life that most teenage girls would envy.

The 18-year-old was a cheerleader who worked during the summer at a camp for kids with disabilities. After graduating with honors, the Carlisle, Ohio, native planned to attend the University of Cincinnati to study nursing. Other students noticed that Richardson — part of the high school class of 2017’s popular crowd — was always well put-together.

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“Her makeup had to be so-so,” a classmate tells PEOPLE. “Her clothes had to be so-so, her hair had to be perfect.”

Beneath that exterior, however, things were apparently anything but.

Last July, after receiving a tip from a doctor that Richardson may have delivered a stillborn baby, police searched the family’s property where they said they found the charred remains of a newborn girl in Richardson’s backyard — then arrested the teen for aggravated murder, involuntary manslaughter, child endangerment, tampering with evidence and gross abuse of a corpse.

The motive, investigators allege, was Richardson’s fixation with perfection. She and her mother “were pretty obsessed” with appearances, prosecutors contend.

“She was described as a good girl, and I think that perception is one that Skylar wanted to perpetuate,” Warren County, Ohio, Prosecutor David Fornshell told reporters at a press conference last year, before a judge placed a gag order on the case in August.

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Richardson has entered not guilty pleas to the charges she faces. She is expected to stand trial later this year.

Her attorney has not publicly offered a defense but reportedly insists she did not kill the infant — “She is a good person, a high honors student,” he told reporters. “She has never been in any trouble of any kind.”

However, according to Fornshell, investigators believe Richardson killed, burned and buried her child, a full-term baby, within hours of giving birth in early May, just two days after she had attended her senior prom.

Image zoom Brooke “Skylar” Richardson Charles Rittgers

The exact cause of death, Fornshell said, may never be known because of the burning and decomposition of the body.

Richardson, her attorney and her parents declined PEOPLE’s requests for interviews. But some of her relatives, including both sets of grandparents, spoke with Cincinnati Magazine last year to defend her against what they contend has been one-sided coverage of the case — including comments made by the prosecution alleging those close to Richardson likely suspected she was pregnant. (No one else has been charged with any wrongdoing and the father of her child has not been publicly identified.)

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“Every single female member of our family is hurting, they are all beating themselves up over that,” the magazine quotes the girl’s uncle, Jay, as saying.

“They never guessed and they would have supported her,” he said.

In their interview, Richardson’s family claimed she suffered from eating disorders and actually delivered a stillborn daughter. They disputed that the infant’s remains were burned.

Image zoom Brooke “Skylar” Richardson Warren County Sheriff's Office

Her aunt Vanessa said, “Skylar is a pleaser, and she was already blaming herself about the baby being stillborn. She kept wrestling with the distressing idea that she may have somehow caused the baby to be born stillborn, and I think investigators twisted that around to prove that she is guilty of murder.”

RELATED VIDEO: Relatives of Former Cheer Coach Accused of Killing Newborn Say Baby Was Stillborn

While the prosecution and defense will present their evidence in court, some in the community say that, in retrospect, there were signs of what was to come.

“She was showing at prom,” says a classmate. “I didn’t realize it until people were talking about it. I looked at the pictures, and it was pretty obvious.”