Fashion designer Kate Spade, a hallmark in the handbag industry, was found dead Tuesday in New York in an apparent suicide, law enforcement officials told WNBC.

A housekeeper found Spade, 55, hanging from a red scarf on a bedroom door in her Park Avenue apartment around 10:30 a.m., the officials reported. A note was found nearby, but the contents of the note weren't immediately released.

Spade suffered from mental illness, her older sister told The Kansas City Star, saying that a suicide "was not unexpected."

Born in Kansas City, Missouri, Spade rolled out her own line of handbags with her husband, Andy, in the 1990s — before expanding it to jewelry and clothing. Their first retail shop opened in New York's SoHo neighborhood.

The Spades sold a majority share of the business to Neiman Marcus in 1999 and the rest to Liz Claiborne in 2006. (Claiborne changed the name to Fifth & Pacific in 2012.)

The designer, whose birth name was Katherine Noel Brosnahan, met her husband while she was studying at Arizona State University. The couple were married for more than two decades. In addition to her husband, who is the brother of actor-comedian David Spade, survivors include their 13-year-old daughter, Frances Beatrix Spade.

Since selling their business, the Spades have gone on to work on philanthropic ventures and launch an accessories and footwear label, Frances Valentine.

Andy said in an interview with Business of Fashion in 2016 about working with his wife: "It's a true team. Kate never wanted to be in the front. [At Kate Spade] you ended up being the one on the front lines all the time, which you didn't really want to do. ... Kate knows what she wants to wear and she really focuses on her taste and style. I bring in the more conceptual ideas."

Last year, Coach, now known as fashion house Tapestry, bought the Kate Spade brand in a $2.4 billion deal. Today, there are more than 150 Kate Spade-branded shops globally, according to the company's website.

"We at Kate Spade New York just learned of the incredibly sad news that Kate Spade has passed," a Kate Spade spokeswoman later told CNBC.

"Although Kate has not been affiliated with the brand for more than a decade, she and her husband and creative partner, Andy, were the founders of our beloved brand," she said. "Kate will be dearly missed. Our thoughts are with Andy and the entire Spade family at this time."

Tapestry, which also owns Stuart Weitzman, saw its shares dip more than 2 percent on the news of Spade's death Tuesday afternoon. The stock was later only down around 1 percent.

To get help: Call the National Suicide Prevention Lifeline at 1-800-273-8255.