The Justice Department has sent a letter to tech billionaire Elon Musk's America PAC warning that his $1 million sweepstakes giveaway to registered voters in swing states may violate federal law, a source familiar with the matter confirmed to ABC News Wednesday.
The letter from the Election Crimes Branch of the DOJ's Public Integrity Section was sent to Musk's PAC in recent days, the source said.
Musk, who has been campaigning for former President Donald Trump, announced the lottery-style giveaway over the weekend, pledging to give away $1 million a day to a randomly selected swing-state resident who agrees to sign his PAC's petition supporting the First and Second amendments.
MORE: Video: Elon Musk's PAC pays out third $1 million check to voterTo qualify, the person must be a registered voter -- leading experts to question whether the lottery could violate federal law that bars individuals from paying people to register to vote.
As of Tuesday, Musk's PAC had given away four $1 million checks.
It's unclear whether the Justice Department has determined that the giveaway is outright illegal.
The independent news site 24Sight News was first to report news of the letter Wednesday.
Officials with the Justice Department declined to comment to ABC News.
Representatives for Musk and his America PAC did not immediately respond to a request for comment.