These are the faces of innocence.

First pictures of a pair of tragic infant twins in Pittsburgh, one of whom was allegedly killed by a “trusted” babysitter last week, have emerged, with the bubbly smiles of 6-week-old Leon and Ari Katz beaming from a set of now heartbreaking photos posted online.

Friends collecting donations for Ethan Katz and wife Savannah Roberts described the couple’s “unbearable loss” after Leon died on Father’s Day — allegedly at the hands of family friend and California PhD student Nicole Virzi, who is believed to be the daughter of a Manhattan cardiologist.

“Leon Katz, a beautiful and healthy six-week old baby boy, was tragically killed under horrific circumstances on June 16, 2024,” friends wrote on a GoFundMe for the couple which has already brought in more than $50,000.

“Leon will always be remembered as a happy, smiley, goofy baby boy. His untimely and tragic death has deeply impacted the Pittsburgh community, occurring on Ethan’s first Father’s Day and the parents’ first wedding anniversary.” 

The couple left Leon in Virzi’s care while rushing Ari to the hospital with a mysterious injury to his genitals, which Virzi, 29, had alerted them to, authorities said.

While the first-time parents were caring for Ari, Virzi claimed Leon had fallen out of his bouncer chair while she stepped away to get a bottle, according to the Daily Mail, which cited police and court records.

But doctors found the injuries “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 WTAE.

“A trusted family friend has been arrested for homicide, child endangerment, and aggravated assault that the boys experience,” according to the GoFundMe.

Virzi’s LinkedIn, which has now been deleted, indicated she is a fifth year Ph.D. Candidate at SDSU/UC San Diego Joint Doctoral Program in Clinical Psychology.

Virzi, who is also accused of abusing Ari, is being held without bail at the Allegheny County Jail and is due in court Friday.

She’s denied the allegations.

The family now faces “significant financial burdens,” the couple’s friends wrote on the fundraising platform, adding, “Funds raised will cover funeral expenses, medical bills resulting from injuries sustained by both Leon and Ari, essential baby supplies, and relocation costs as they navigate this difficult time.”

Virzi is believed to be the daughter of Mount Sinai cardiologist Peter J. Virzi. A man who answered the phone at one of Nicole’s siblings’ homes and identified himself as the suspect’s father said slammed a Post reporter as “inappropriate” and a “horrible person” before hanging up.

“Our client denies these allegations. She is a loving person and a friend to these people and would never harm anyone’s child, let alone theirs,” Virzi’s attorney David Shrager told Pittsburgh’s WTAE.

“She’s going to be 30 years old. She’s a Ph.D. student. She is long-term friends with the family in this situation. As I’ve said, it doesn’t show any criminal history in her background and we’re anxious to get our day in court.”

Savannah Roberts is also a fifth-year PhD student in Clinical and Developmental Psychology at the University of Pittsburgh.