Three-time world champion and Olympic silver medallist Kelly Catlin has died aged 23.
USA Cycling confirmed the news with tributes pouring in for the Olympic silver medallist from the Rio 2018 Games.
Catlin also landed three straight team pursuit world titles on the track from 2016 to 2018 and was studying for a graduate degree at Stanford University.
“We are deeply saddened by Kelly’s passing,” said USA Cycling president and chief executive Rob DeMartini.
“We will all miss her dearly. Kelly was more than an athlete to us and she will always be part of the USA Cycling family.
“Our thoughts and prayers are with the Catlin family. This is an incredibly difficult time and we want to respect their privacy.
“The entire cycling community is mourning this immense loss. We are offering continuous support to Kelly’s team-mates, coaches and staff. We also encourage all those who knew Kelly to support each other through the grieving.”
Catlin's brother Colin said his sister killed herself in a Facebook post.
"She's the one person I had shared almost my. entire life with, and I shall miss her terribly," he wrote.
An alumna from the University of Minnesota, Catlin was a graduate student at Stanford University, where she studied computational mathematics, Catlin wrote in a VeloNews blog about the struggles of studying and competing in professional sport.
"After all, I somehow make everything work, right? Sure. Yeah, that's somewhat accurate. But the truth is that most of the time, I don't make everything work."
Retired professional cyclist Michael Sayers wrote Catlin's passing was a "monumental loss for the cycling community in the USA.
For confidential support call Samaritans on 116 123.
In the US, you can contact the National Suicide Prevention Lifeline for free on 800-273-8255
You can also contact the following organisations for confidential support: Mind; Beat Eating Disorders, NHS, Mental Health Foundation
