HILLSBOROUGH, N.J. (CBSNewYork) — A New Jersey community is in shock after two children were found dead in the backseat of a car on Tuesday morning.

Their mother, Yuhwei Chou, is now facing murder charges. She underwent a mental evaluation and made her first court appearance Wednesday afternoon in Somerset County.

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The 36-year-old kept her head down at times, only speaking when the judge asked if she had a question for the public defender, which she did not, CBS2’s Lisa Rozner reported.

As police continue their investigation, neighbors told CBS2’s John Dias they are overcome with emotion over the heartbreaking incident.

“I don’t know if there’s any way you can process this. I just feel so sad for their family,” neighbor Helen Wang said.

Somerset County prosecutors said 7-year-old Samantha Ross and her 10-month-old brother, Paul Ross, were found in the vehicle near Mountain View Road in Hillsborough, about 10 miles north of the family’s home in Skillman, which is located in Montgomery Township. Chou was behind the wheel, and the kids were bound and restrained in their booster seats, showing no signs of life.

Robert Long’s son was driving a tow truck when he spotted the car just before 8 a.m. Tuesday.

“He just said he found a lady in the ditch and he said he asked her if she was alright. She said no, I think, and then he [saw] the babies. Then he called the cops right away,” Long said.

Samantha Ross was a second grader at The Waldorf School of Princeton. The school’s administrator told CBS2 the school community “is shocked and deeply saddened” by her passing. Grief counselors are on-site to support students and staff.

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Neighbors said the little girl, nicknamed “Sam,” was rambunctious, adding not hearing her play across the street will be an eerie reminder that she’s gone.

“She had set up a little lemonade stand at one time, even though we have no cars coming down our street, ever,” Wang said. “She’s very spunky. She is a little spitfire, adorable, totally just the cutest little thing, but, yeah … just a little angel.”

Neighbors said they have seen officers at the family home before.

“Over the years, I had seen some. Police cars would come occasionally. We never know what any of that was about,” said Austen Wang Bailey.

Helen Wang said if she knew something was wrong and the kids were in danger, she would have stepped in to help.

“I never even saw the little boy. I understand he was a beautiful little boy,” she said.

The children’s father, James Ross, is an engineer at Bloomberg’s New Jersey offices. CBS2 has been unable to reach him for comment.

Chou is due back in court next Tuesday.

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CBS2’s Lisa Rozner contributed to this report.

John Dias