Michelle Trachtenberg‘s cause of death will remain undetermined after her family declined an autopsy.

Earlier this week it was announced the actress, best-known for appearing in shows including Buffy the Vampire Slayer and Gossip Girl, had died aged 39.

She was reportedly found ‘by her mother around 8am local time on Wednesday in a luxury apartment complex in New York.

Police then said she had been ‘unconscious and unresponsive’ and her death was not being investigated as suspicious.

Now, the New York City Office of the Chief Medical Examiner has announced that an autopsy will not be done to investigate her cause and manner of death.

The New York Post has reported that the actress’ family requested an autopsy was not conducted.

The medical examiner’s office would have automatically undertaken an autopsy if foul play or criminality had been suspected, but as there was none, it did not overrule the family’s objections.

The publication also reported the office said it was ‘obligated to honour the family’s request due to the state’s public health law’, which confined the medical examiner to conducting an external examination, which limits what can be determined.

Police sources had previously told ABC News Trachtenberg had recently undergone a liver transplant and may have suffered complications.

However she never publicly spoke about these claims.

Soon after her death, a spokesperson for the family released the following statement: ‘It is with great sadness to confirm that Michelle Trachtenberg has passed away. The family requests privacy for their loss. There are no further details at this time.’

Last year the actress hit back at ‘haters’ after she faced frequent comments about her appearance on social media.

After posting a selfie, she wrote in her caption: ‘Fun fact. This is my face. Not malnutrition no problems. Why do you have [to] hate? Get a calendar.’

In another instance, she wrote: ‘I’ve received several comments recently about my appearance. I have never had plastic surgery. I am happy and healthy. Check yourself haters.’

After making her acting debut as a child star on Nickelodeon, including in The Adventure of Pete & Pete and Harriet the Spy.

She went on to play Dawn Summers in Buffy,Georgina Sparks in Gossip Girl and also starred in the 2005 movie Ice Princess.