Maine authorities arrested a Pennsylvania woman on Sunday, a day after her 3-year-old daughter died in a hot car.

Kelly Brown, 40, was visiting family when her toddler daughter and dog were found dead in her vehicle parked in Milford. The pair were left in the car for more than 15 hours — which Brown claimed occurred after she was swept away in a river while throwing out trash, according to WCAU.

Brown allegedly stated that she wanted to teach her daughter about protecting nature, as they saw a lot of trash at camping sites during their trip from Pennsylvania to Maine.

She said they stopped at a gas station in Milford to clean up the parking lot before leaving her daughter and dog in her locked car while she got a trash bag, WCAU reported.

According to the Portland Press Herald, Brown’s mother requested a welfare check shortly after Brown and her daughter failed to show up at a relative’s home in Clifton on Thursday.

Police eventually pinged Brown’s cellphone, leading them to the gas station in Milford — where they found the deceased girl and dog.

Maine State Police said an official determination is pending, but the medical examiner believes Brown’s daughter died from hyperthermia.

Brown allegedly told police that it took hours to fight her way out of the river. Officers noted that her clothes appeared dry — to which she claimed was because it had been hours since she crawled to the river and tried to get back to her car, according to the Portland Press Herald.

Surveillance footage from 6 a.m. Saturday allegedly showed Brown leaving the vehicle at 6 a.m. and returning 15 hours later, WLBZ reported.

Brown was charged with manslaughter. Her bail was set at $50,000.

[Feature Photo: Penobscot County Sheriff’s Office]