Docker today announced that Ian Murdock, a member of the startup’s technical staff and a former Sun and Salesforce employee known for founding the Debian Linux operating system, has passed away. He was 42.

A cause of death was not provided in the blog post announcing the news. Docker declined to comment. The San Francisco Police Department did not immediately have information on Murdock’s cause of death.

Murdock’s Twitter account posted several tweets (PDF) on Monday that suggested he had been involved in an incident involving police, and one tweet said that he would commit suicide that night. Some people speculated that his account had been hacked. It has since been deleted.

“Ian helped pioneer the notion of a truly open project and community, embracing open design and open contribution; in fact the formative document of the open source movement itself (the Open Source Definition) was originally a Debian position statement,” Docker chief executive Ben Golub wrote in the blog post. “It is a testament to Ian’s commitment to openness and community that there are now more than 1,000 people currently involved in Debian development.”

Murdock created Debian in August 1993 — he is the “ian” in the project’s name. In a biography on his personal website he talked up the project’s accomplishments. “With its integrated software repositories anyone could contribute to, Debian arguably had the industry’s first (albeit primitive) ‘App Store,'” he wrote.

In the past few years Docker has popularized Linux containers, and there is significance in his arrival at the startup, as he is highly regarded in the Linux world. Many Debian users responded to the Monday tweets with sympathy and support.

Condolences from people in the Debian and broader Linux community can be sent to in-memoriam-ian@debian.org.

Rest in Peace Ian. You left a mark and made the world better. We miss you. https://t.co/AQXiCnTGdd — Solomon Hykes (@solomonstre) December 30, 2015

We mourn the loss of Ian Murdock – he made immeasurable contributions to OSS – The circumstances are puzzling though https://t.co/RFd4IUBVqE — Werner Vogels (@Werner) December 30, 2015

Ian Murdock was a friend. I am shocked and saddened. My deepest condolences to his family and loved ones. May he rest in peace. — jzemlin (@jzemlin) December 30, 2015

RIP Ian Murdock (1973–2015), the founder of Debian project. You'll be missed. pic.twitter.com/Nq7yly3D4s — Linux (@Linux) December 30, 2015