Sprint is taking aim at two former employees who are now working for cable company Charter Communications, alleging they stole patents and trade secrets worth billions of dollars.

As first reported by the Kansas City Business Journal, Sprint's lawsuit claims two former employees – Paul Woelk and Craig Cowden – disclosed confidential information to cable company Bright House Networks while still employed at Sprint.

"Mr. Woelk and Mr. Cowden knew their actions were improper," Sprint wrote in its lawsuit. "Sprint neither knew about nor would have authorized such disclosures if it had known."

Both executives subsequently left Sprint and joined Bright House, which was subsequently acquired by Charter.

Both executives are now high-level players at Charter. Woelk is Charter's VP of business planning, while Cowden is one of the top executives in Charter's burgeoning mobile business.

Lawyers at Charter alerted Sprint late last year about the issue. They discovered 3,500 confidential Sprint documents on Woelk's Charter-issued computer in a folder titled "Sprint My Documents."

"Until Charter’s counsel was forced to alert Sprint’s outside counsel in the Fall of 2019 of the improper disclosure of Sprint’s HC [highly confidential] Trade Secrets, Sprint had no knowledge of any disclosure," the operator wrote in its lawsuit.

At issue is voice over IP (VoIP) technology. "Sprint spent years and millions of dollars investing in, developing, and optimizing its VoIP technology and financials, resulting in hundreds of patents and trade secrets. Instead of developing their own technology and financial information, Defendants stole Sprint’s long-term investments, technology, and property," Sprint wrote.

Officials for Sprint and Charter declined to comment.

Sprint has a lengthy history in attacking cable companies and others over VoIP technology. It has filed patent infringement charges against the likes of Time Warner Cable (which was also acquired by Charter), Cox and Vonage, among others.

Sprint appears to be in the final stages of closing its proposed merger with T-Mobile. Meantime, Charter is directly competing with Sprint and T-Mobile in the mobile industry via its Spectrum Mobile offering. Charter's Spectrum Mobile service piggybacks on Verizon's wireless network.

— Mike Dano, Editorial Director, 5G & Mobile Strategies, Light Reading | @mikeddano