Michelle Trachtenberg, who rose to fame as a child star in the 1990s and 2000s, has died aged 39, the New York Police Department told CBS News, the BBC’s US partner.

The American actress was best known for playing Buffy the Vampire Slayer’s younger sister Dawn Summers, and later took on the role of manipulative socialite Georgina Sparks in Gossip Girl – which ran from 2007 to 2012 – as an adult.

Her death is not being treated as suspicious, police said.

Trachtenberg made her film debut in Harriet the Spy in 1996, and she appeared in several Nickelodeon productions.

BBC News has reached out to Trachtenberg’s representatives for comment.

Police in Manhattan said they responded to an emergency call on Wednesday morning, and they found Trachtenberg “unconscious and unresponsive”. She was “pronounced deceased at the scene”.

“Criminality is not suspected. The medical examiner will determine the cause of death. The investigation remains ongoing,” the NYPD said in a statement.

Trachtenberg got her start in acting at three years old on the Nickelodeon television series The Adventures of Pete & Pete.

In the early 2000s, she was nominated for several acting awards – including a Daytime Emmy Award – for her role in Buffy the Vampire Slayer.

She also starred in films including EuroTrip, Ice Princess, Killing Kennedy, and Sister Cities.

Trachtenberg first appeared in Gossip Girl in 2008. She returned to the role for two episodes of the second season of HBO Max’s reboot in 2023.

Her last major acting role was in 2021 as the host of a true-crime docuseries Meet, Marry, Murder, which appeared on digital streamer Tubi.

In 2021, Trachtenberg accused Buffy the Vampire Slayer creator Joss Whedon of inappropriate behaviour on set after her co-star Charisma Carpenter said she had been left traumatised due to the treatment she received from Whedon.