Theranos founder Elizabeth Holmes made headlines for a number of outrageous things she did when she was considered a Silicon Valley sensation, but some close to the disgraced former CEO have only recently revealed her stunts also included changing her voice to make it sound lower.

Holmes, 35, is the subject of the HBO documentary “The Inventor: Out for Blood in Silicon Valley,” which chronicles the rise and fall of her company, Theranos. Her company claimed it discovered a new way of conducting blood testing that would allow them to perform dozens of tests with just a few droplets of blood.

The strange timbre of Holmes's voice was revealed after Stanford professor Dr. Phyllis Gardner told ABC Radio’s podcast “The Dropout” that she recalled Holmes’ voice being higher when they first met.

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“When she came to me she didn’t have a low voice,” Gardner said. “When I next saw her again was at the Harvard Medical School board meeting where she was being introduced. She says with this low voice and I’m like, ‘Oh my god.’ It was quite off."

Ana Arriola, a former Theranos employee, backed up the claim in the podcast, saying she and her colleagues heard the then-CEO “fall out of voice.”

“It was maybe at one of the company parties, and maybe she had too much to drink or what not, but she fell out of character and exposed that that was not necessarily her true voice,” Arriola said. “Maybe she needed to be more convincing to project a persona within a room among male [venture capitalists], I'm not really quite sure.”

Arriola also noticed Holmes’ wardrobe had changed from “frumpy Christmas sweaters” to all black. She believed Holmes changed her attire to mirror Steve Jobs who wore black turtlenecks. However, Holmes told Glamour in 2015 that she has worn black turtlenecks since she was young.

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"My mom had me in black turtlenecks when I was, like, eight," she said. "I probably have 150 of these. [It's] my uniform. It makes it easy, because every day you put on the same thing and don't have to think about it—one less thing in your life. All my focus is on the work. I take it so seriously; I'm sure that translates into how I dress."

The demise of Theranos began following a Wall Street Journal investigation that discovered the company’s break-through technology was a sham, and it had been using average equipment for the vast majority of its blood tests. The FBI, Department of Justice and the Securities and Exchange Commission began to investigate Theranos following the report. Theranos shut its doors in September 2018 and Holmes was eventually charged with “11 criminal felony counts, including wire fraud and conspiracy,” Vanity Fair reported.

The Associated Press contributed to this report.