Officials on the scene said they could not give more detail while the investigation is still ongoing.
"I don't think everyone knew how f*****g amusing she was".
Spade created a line of sleek handbags in the early 1990s that created a smash on the world fashion scene. In 2006, the company then known as Liz Claiborne bought the brand, and Kate and Andy Spade left the company soon after. That company was sold to luxury competitor Coach past year in a $2.4 billion deal.
In 2016, Kate launched a new brand called Frances Valentine, named after her daughter.
The New York Police Department confirmed her death, under her birth name of Katherine Noel Brosnahan. Spade took that time to focus on her family, as she and her husband had welcomed a daughter.
She started her career in fashion as an accessories editor at the now-closed Mademoiselle magazine before launching her own company in 1993.
The family's statement to the New York Daily News said, "We are all devastated by today's tragedy".
Born Kate Brosnahan in Kansas City in 1962, she graduated with a degree in journalism from Arizona State University in 1985.
Who was Kate Spade? "She had a quirky visual language that captivated Bat Mitzvah girls and artists alike", Lena Dunham tweeted. Her impact on the fashion and accessories world will forever be felt by those who knew her and those who were fans of her work. The National Suicide Prevention Lifeline (1-800-273-8255) provides 24/7, free, confidential support for people in distress, as well as best practices for professionals and resources to aid in prevention and crisis situations.