A Ph.D. student charged with killing her friend's newborn baby and abusing the infant's twin brother while babysitting them in Pennsylvania could be sentenced to the death penalty if she is convicted, as prosecutors revealed they plan to seek capital punishment.

Nicole Virzi, 30, was charged with homicide, aggravated assault and child endangerment after allegedly abusing and killing six-week-old Leon Katz while the child's parents, Ethan Katz and his wife Savannah Roberts, took the baby's twin brother Ari to the hospital on June 16.

Virzi was later accused of abusing Ari.

The Alleghany District Attorney’s Office said in court Friday that it intends to seek the death penalty against Virzi, the Pittsburgh Post-Gazette reported.

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Nicole Virzi, 30, was charged with homicide, aggravated assault and child endangerment. (Allegheny County Jail)

Prosecutors filed notice that they will pursue the death penalty, citing several abuses Virzi allegedly committed in the baby's death, including allegations that she killed him by means of torture, according to the outlet.

Pennsylvania Gov. Josh Shapiro, a Democrat, has said he would not sign any death warrants while he is in office.

Virzi claimed that Leon fell from his bouncer chair when she left him by himself for a moment to grab a bottle.

However, doctors found the injuries to both twins to be "consistent with having been sustained as a result of child abuse, as these are inflicted injuries that are not natural and not accidental," according to a criminal complaint, WTAE reported.

Leon's death was ruled a homicide.

The medical examiner ruled Leon's cause of death to be blunt force trauma to the head. A head CT scan found the child suffered a severe skull fracture to the left side of the head and that he had several brain bleeds.

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Ethan Katz and Savannah Roberts holding their twin boys before one was allegedly killed by a family friend.  (GoFundMe)

A GoFundMe page started to support the family after the baby's death described Virzi as a "trusted family friend."

Virzi, who was a clinical psychology student at UC San Diego specializing in research into depression's effect on human behavior, is from California but was staying in a Pittsburgh-area Airbnb at the time of the child's death.

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Screen grab of Nicole Virzi's bio as a Ph.D. student at San Diego State University/UC San Diego Joint Doctoral Program in Clinical Psychology's website.  (San Diego State University/UC San Diego Joint Doctoral Program in Clinical Psychology)

Her lawyer, David Shrager, said his client maintains her innocence. She has pleaded not guilty.

She has no criminal history, is backed by "a loving and supportive family," and is a "close family friend of the deceased child's parents and has a long relationship with them," Shrager previously told Fox News Digital.

Fox News' Chris Eberhart contributed to this report.