Mesosphere's Jessie Frazelle. YouTube/Container Camp Last month, word broke that a star engineer for the super-hot startup Docker, Jessie Frazelle, was leaving to join another hot startup, Mesosphere.

Such career leaps are often routine. But in this case, Frazelle was known as "THE face of Docker engineering to the community," as one person on Twitter put it.

She was active on the speaker circuit and had contributed so much code to the Docker project that she was considered one of Docker's main builders. Docker helped invent a programming industry called "containers," which helps apps move from the programmer's computer to the cloud without breaking.

A tweet from another female engineer claimed that Frazelle was "harassed out" of Docker:

The fact that Frazelle had been subject to brutal harassment had been well-known for a while. Last July, a fed up Frazelle wrote about these experiences in a post that went viral:

Ever since I started speaking at conferences and contributing to open source projects I have been endlessly harassed. I've gotten hundreds of private messages on IRC and emails about sex, rape, and death threats. People emailing me saying they jerked off to my conference talk video (you're welcome btw) is mild in comparison to sending Photoshopped pictures of me covered in blood.

I wish I could do my job, something I very obviously love doing, without any of this bull—. However that seems impossible at this point.

It's worth repeating: This person received horrific threats because she's good at her job and out teaching others how to use an up-and-coming programming technology.

She's not alone. The tech industry is riddled with similar stories of threats and sexism toward women, as if it's just one big frat house operating under 1950s "Mad Men" rules.

Naturally, the tweet saying that she had been "harassed out" picked up steam, too, so much so that on Friday Docker tweeted from its main account an internal email from CEO Ben Golub to employees denying the accusation.

In that email, Golub wrote:

As you know, Jessie was being harassed by anonymous members of the community, and we took it very seriously. https://news.ycombinator.com/item?id=9835375. We threw our resources (including hiring private investigators, involving law enforcement, changing internal systems) to try and prevent this harassment. We always stood by Jessie.

While Jessie did resign from Docker for another opportunity, we spoke to her about all of the reasons for her leaving. She did not at any time claim harassment from people inside Docker. We parted ways on good terms.

Click here for a larger version of the email.

We asked Docker if hiring private investigators and going to the police worked to deter any of the culprits who were threatening its employee. The company declined to comment.

No doubt Frazelle's career will continue to soar at Mesosphere, a company building a management system for containers with all the early earmarks of success.

Frazelle declined to comment when we reached out to her, but she did tweet: