A top lawyer for Twitter owner Elon Musk says the platform has "serious concerns" that Facebook parent Meta hired "dozens of former Twitter employees" in order to build its new "copycat" Threads app — accusations that Meta denies.

In a Wednesday letter addressed to Meta Platforms CEO Mark Zuckerberg, Quinn Emanuel Urquhart & Sullivan LLP partner Alex Spiro, a longtime lawyer for Musk and his businesses, notified the rival tech executive that Twitter's new parent company plans "to strictly enforce its intellectual property rights."

Spiro asserted that in rolling out its Threads social media app, which launched Wednesday, Meta relied on the work of "dozens of former Twitter employees" who "have improperly retained Twitter documents and electronic devices."

"With that knowledge, Meta deliberately assigned these employees to develop, in a matter of months, Meta's copycat 'Threads' app with the specific intent that they use Twitter's trade secrets and other intellectual property in order to accelerate the development of Meta's competing app," the letter said.

In April, Twitter was hit with a proposed class action from former employees following Musk's $44 billion deal to take the company private.

Competition is fine, cheating is not

— Elon Musk (@elonmusk) July 6, 2023In response to reports of the letter, Musk wrote in a Twitter post, "Competition is fine, cheating is not."

"Twitter has serious concerns that Meta Platforms has engaged in systematic, willful and unlawful misappropriation of Twitter trade secrets and other intellectual property," Spiro wrote.

In addition to alerting the company of the prospect of a lawsuit, Spiro's letter asserted that Meta is "expressly prohibited from engaging in any crawling or scraping of Twitter's followers or following data."

The letter did not specify which former Twitter employees Meta had allegedly assigned to its Threads development team or what intellectual property Meta purportedly misappropriated, outside of "trade secrets and other highly confidential information."

Aggressive enforcement of intellectual property rights is a bit of a change for Musk, who in 2014 announced that his electric car company, Tesla, would open up its patents to other manufacturers interested in using its technology. As recently as last year, during an appearance on the CNBC show "Jay Leno's Garage," Musk declared that "patents are for the weak."

Meta spokesman Andy Stone responded to Spiro's claims in a post on Threads, saying that "no one on the Threads engineering team is a former Twitter employee."

"That's just not a thing," Stone said.