Michelle Trachtenberg’s mom talked to her the night before she was found unresponsive in her New York City apartment, according to a new TMZ report.

The NYPD previously confirmed to PEOPLE that officers responded to a 911 call at 1 Columbus Place in New York City around 8:00 a.m. on Wednesday, Feb. 26.

“Upon arrival, officers observed a 39-year-old female unconscious and unresponsive. EMS responded to the location and pronounced the victim deceased. Criminality is not suspected,” they said.

According to TMZ, it was Trachtenberg’s mom, Lana, who found her “unresponsive, lying on her back in bed,” causing her to alert police and paramedics.

Lana had last seen her daughter alive at 10 p.m. Tuesday, and “she was clearly active despite her health concerns,” reported TMZ. The NYPD confirmed to PEOPLE that an investigation into Trachtenberg’s death remains ongoing but could not confirm the details of TMZ’s report.

While a cause of death has not been announced, multiple sources confirmed to PEOPLE that Trachtenberg had recently undergone a liver transplant. A source told ABC News that may have led to health complications.

Although Trachtenberg had never publicly discussed any health conditions, she responded to commenters on Instagram in January when they suggested she was unwell.

“I’ve received several comments recently about my appearance. I have never had plastic surgery I am happy and healthy. Check yourself haters,” she wrote next to a Jan. 18 Instagram upload.

A day later, she shared similar sentiments next to another Instagram selfie, writing, “Fun fact. This is my face. Not malnutrition no problems. Why do you have to hate? Get a calendar.”

An insider told PEOPLE following her death that Trachtenberg was “really down emotionally” and had been dealing with “health issues.”

“She told friends she was struggling. She was really, really sick and open with those in her circle about how much she was struggling,” said that insider, who claimed she looked “pale, gaunt” and “very thin.”