A teenage cheerleader who was described as a "good person" -- despite allegedly killing and burning her infant before burying the baby in her backyard -- pleaded not guilty to aggravated murder charges in an Ohio court on Monday.

A judge order Brooke "Skylar" Richardson, 18, to house arrest and set her bond to $50,000, according to WCPO. Prosecutors asked for a $1 million bond. The judge said he set the bond to ensure Richardson would appear in court, adding he believed she wasn't a flight risk.

Warren County prosecutor David Fornshell said Richardson "purposefully caused the death of the child" who police believe was killed on May 6 or May 7. The body of the newborn was discovered outside of her Carlisle home, about 40 miles north of Cincinnati, on July 14.

The exact cause of the baby's death may never be known, because the body was badly burned and decomposed when authorities uncovered the remains.

"To be frank with you, I'm not sure we ever will provide to you the exact medical cause of death, and the reason for that is because the child was, after death, burned and subsequently buried, and there was significant decomposition to the body," Fornshell said.

Richardson was initially charged with reckless homicide, but charges were later upgraded to include aggravated murder, involuntary manslaughter, child endangering, evidence tampering and corpse abuse -- all of to which she pleaded not guilty.

Richardson's attorney called the teenager, who used to be a cheerleader and honor student at Carlisle High School, a "good person." Richardson planned to attend the University of Cincinnati in the fall.

But Fornshell said he believed the teenager's obsession "with appearances and how things appear to the outside world" may have been the driving force that led the "good" girl to kill, FOX19 reported.

"Skylar and her family, particularly her mother, were pretty obsessed with external appearance and how things appear to the outside world, and if members of the community were to find out that the Richardson girl was pregnant, and perhaps gave birth, and even if, after giving birth, gave that child up for adoption, that was something that was simply not going to be accepted in that household, at least by Skylar and her mother," Fornshell said in court Monday.

It's unclear who the father of Richardson's baby is. Richardson is the only person charged in the case.

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