Kate Brosnahan Spade, the fashion designer and businesswoman, hanged herself in an apparent suicide Tuesday at a Manhattan apartment, according to a New York Police Department source.

Police responded at 10:10 a.m. after Spade was found by her housekeeper, NYPD Chief of Detectives Dermot Shea said. A suicide note was found at the scene, he said.

Spade, 55, started Kate Spade New York in 1993 and opened her first shop in the city three years later, the company's website states.

"Debuting with just six silhouettes, she combined sleek, utilitarian shapes and colorful palettes in an entirely new way," the site says.

Best known for its colorful handbags, Kate Spade New York has more than 140 retail shops and outlet stores across the United States and more than 175 stores internationally, the site states.

Over time, she distanced herself from her business.

In 1999, she and her husband, Andy Spade, sold 56% of the brand to Neiman Marcus for $33.6 million. Liz Claiborne acquired the company in 2007, and Spade left her namesake brand. The luxury fashion company Coach announced plans in May 2017 to buy Kate Spade for $2.4 billion.

Kate Spade New York issued a statement confirming the "incredibly sad news" of their eponymous founder's death.

"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," the statement said. "Kate will be dearly missed. Our thoughts are with Andy and the entire Spade family at this time."

"We honor all the beauty she brought into this world," the company said in a tweet.

Spade was found hanged by a scarf she allegedly tied to a doorknob, an NYPD source said.

Her death prompted an outpouring of grief among fans and her company's customers, including Chelsea Clinton and Ivanka Trump.

"Everyone remembers their first Kate Spade," CNN White House reporter and former fashion editor Kate Bennett said. "(The brand) became one of those accessible but quirky fun, timeless labels that everyone had to have, and her rise was synonymous with her name."

For many women, a Kate Spade handbag was a bridge between Main Street clothes and high-end fashion, and it functioned as a symbol of professional achievement.

The Council of Fashion Designers of America, which held a star-studded awards ceremonyMonday night, posted a statement from Diane von Furstenberg and Steven Kolb saying they were devastated to hear of Spade's death.

"She was a great talent who had an immeasurable impact on American fashion and the way the world viewed American accessories," the statement said.

Cindi Leive, a former editor-in-chief of Glamour magazine, said that part of Spade's legacy is that she put her entire personality into her work.

"She understood that women are going to respond to things that feel like they're made by a human, that they are expressing someone's personality," Leive said.

"If you put a pulse into it and every fiber of your being, people are going to respond. Now, that's kind of a given. Everybody wants to create their own personal lifestyle brand," she added. "But that was new at the time, and in a lot of ways, the contemporary version of it really came from her."

Before making the jump to designing, she was a senior fashion editor at the fashion magazine Mademoiselle.

Last year, Spade and her husband spoke with NPR's "How I Built This" about how they developed the company into a major lifestyle brand.

"So, Andy and I were out, honestly, at a Mexican restaurant," Kate Spade said, "and he just said, what about handbags? And I said, honey, you just don't start a handbag company. And he said, why not? How hard can it be? (Laughter) I thought, OK, really? He regrets those words."

Joe Zee, a fashion journalist who had worked with Spade, recalled her telling him of the vision to start the handbag line.

"This wasn't something women did or just anyone really did back then in the early '90s," he told CNN. "And to quit a coveted magazine editor's job to really be able to do that ... it was so visionary and so ahead of its time."

"She always had such a great ray of light about her. She was so jovial," Zee said.

Spade's apparent suicide comes as suicide rates in the United States increased from 1999 to 2014 for everyone between the ages of 10 and 74, according to a 2016 study from the Centers for Disease Control and Prevention. For white women, the suicide rate increased by 60% during that period, the study found.

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