Uber made a small splash last month when it hired Lyft's former COO Travis VanderZanden. Kara Swisher said the move "will surely increase tensions between Uber and Lyft, which are now pretty tense as it is." And she was right: Lyft is suing VanderZanden, alleging that he took company secrets along with him to Uber.

The New York Times obtained a copy of the complaint and reports that VanderZanden is accused of taking tens of thousands of confidential files with him after he left Lyft:

The lawsuit accuses Travis VanderZanden, Lyft's former chief operating officer, who left the company in August, of downloading important company information including financial data, information on future product plans and growth statistics. The lawsuit says that Mr. VanderZanden's personal online storage account contained more than 98,000 files and folders after he left the company, according to a copy of the filing obtained by The New York Times. Mr. VanderZanden joined Uber, Lyft's strongest rival, just two months after leaving Lyft.

"VanderZanden's conduct not only breaches the confidentiality agreement, but also breaches fiduciary duties of loyalty and confidence he owed to Lyft as an officer and employee," the suit said.

The lawsuit accuses VanderZanden of stalling his resignation from the company so he could make back-ups of company materials. He allegedly blew off an August 15th meeting with the company's co-founders, in which they were supposed negotiate an agreement, to make the back-ups:

According to the the Times, the suit claims VanderZanden had "second thoughts" before resigning from Lyft. In an email to the company's co-founders disclosed in the lawsuit, VanderZanden wrote "I love you guys like brothers."

His opinions have clearly shifted since then. In a series of tweets that began last night, VanderZanden denied the allegations and took shots at his former employer.

VanderZanden went on to tweet that it was the company norm for employees to use their personal Dropbox account when collaborating on Lyft materials. He later claimed that Lyft's co-founders had not revoked his permissions to view company materials on Dropbox and he did so himself.

Update: Lyft emailed a Valleywag a copy of the lawsuit along with a statement:

We are disappointed to have to take this step, but this unusual situation has left us no choice but to take the necessary legal action to protect our confidential information. We are incredibly proud of the dedicated and people-powered culture that we've fostered to support drivers, passengers and the entire Lyft community and we will not tolerate this type of behavior.

You can read the lawsuit below.

This post, including the headline, has been updated to reflect comments from Lyft about the allegations in the lawsuit.

To contact the author of this post, please email kevin@valleywag.com.

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