Lyft Says Former COO Took Confidential Files With Him to Uber Travis VanderZanden denies the claims that he took secret company information with him when he left one ridesharing company for the other.

There's friendly competition, and then there's what's going on between Uber and Lyft. It's getting colder and colder, more and more nasty between the two San Francisco-based transportation technology companies.

In the latest round of battle, Lyft filed a complaint with the Superior Court of the State of California yesterday afternoon against former chief operating officer Travis VanderZanden, saying that when he left Lyft for rival Uber, he took classified documents with him. The lawsuit accuses him of "breach of written contract -- confidentiality agreement" and "breach of fiduciary duty."

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VanderZanden left Lyft -- the ridesharing company whose drivers affix pink, furry mustaches to their cars -- to join Uber in August.

According to the complaint, "computer forensic evidence" proves that he synced his Lyft laptop with his personal Dropbox account, accessing 98,000 documents. Of those filed, "a significant number" were "Lyft's most sensitive documents," the brief states. Documents found in VanderZanden's personal Dropbox include financial information, strategic planning materials, product plans, international growth documents and private information about Lyft's employees.

Lyft said it was forced to take legal action. "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," the company said in a statement. "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."

Related: Uber Picks Up Lyft's Former COO

Meanwhile, VanderZanden denies the allegations. Last night, he tweeted: "Lyft's PR has lost it, the allegations in their complaint are ridiculous." This morning, he continued his defense, arguing that he did nothing out of the ordinary:

Lyft's PR has lost it, the allegations in their complaint are ridiculous.

— Travis VanderZanden (@travisv) November 6, 2014

"Just to be crystal clear, I did not take any confidential data to Uber. Like many other early employees at Lyft, I used my personal dropbox to collaborate on files. In fact, I was invited to view many of the documents listed in the complaint by the co-founders directly. After leaving Lyft and before joining Uber, I realized they hadn't revoked my invites, so I deleted all remaining files myself. All the facts will come out, but I wanted to clear up the mis-information and protect against this audacious attack on my reputation."

The legal dispute follows a confession from Uber CEO Travis Kalanick in a profile for Vanity Fair that when Lyft was making the rounds raising money from venture capitalists, Uber was unapologetically going back to the same VCs to pitch Uber. "We knew that Lyft was going to raise a ton of money," Kalanick told tech reporter Kara Swisher. "And we are going [to their investors], "Just so you know, we're going to be fund-raising after this, so before you decide whether you want to invest in them, just make sure you know that we are going to be fund-raising immediately after.' "

For a burgeoning industry that depends on strangers interacting cordially and with civility towards one another, the executives of the leading companies in the ridesharing industry are going for each other's jugulars.

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