A Pennsylvania mom is facing charges after her three-year-old daughter and pet dog were both found dead inside a hot car over the weekend in Maine.

Kelly Brown, 40, of Havertown, a Philadelphia suburb, was charged with manslaughter Monday at the Penobscot Judicial Center in Bangor, WCVB reported.

The little girl was found dead alongside the family’s 13-year-old dog, Penelope, on Saturday evening inside the vehicle, which authorities found at a business in Milford, a small town of about 3,000, Maine State Police said.

Brown and her daughter were visiting family in Maine, but after several days without contact, Brown’s mother reported her daughter and granddaughter missing.

Court documents said police found the girl and dog inside the locked car and broke the front window to get inside. Both the girl and the dog were dead.

Autopsy results revealed the girl likely died from being left in the car for nearly 15 hours, according to court documents obtained by News Center Maine. The high temperature in Milford on Saturday was 82 degrees.

Her official cause and manner of the girl’s death are pending additional studies, authorities said.

After Penobscot County Sheriff’s Office deputies discovered the girl’s body, officers located Brown not far from the car and detained her. She was arrested at about 5 a.m. Sunday on the manslaughter charge.

When reporting the pair missing, Brown’s mother told authorities that her daughter had been sharing “bizarre” things on her social media accounts.

Her strange behavior was also detailed in documents obtained by News Center Maine. During police interviews, Brown claimed to be hallucinating and hearing voices that were telling her what to do.

Brown said she and her daughter had been cleaning up trash on their trip, during which they were camping in her car.

She said she went out to collect trash while leaving the toddler and dog in the car, but slipped and fell into the Penobscot River and got swept away.

Officers, however, noted in court documents that Brown’s clothes were not wet when she returned and that her explanation didn’t align with what surveillance footage showed.

Brown appeared in court Monday at the Penobscot County Jail, where a judge placed bail at $50,000 and barred her from making contact with children under the age of 18.