The Philadelphia district attorney’s office has filed a lawsuit seeking to stop Elon Musk’s political action committee from awarding $1m to registered voters in swing states. The lawsuit by the district attorney Larry Krasner accuses the tech billionaire and his America Pac group of attempting to influence voters in the US presidential election with hopes of winning a cash prize. “America PAC and Elon Musk are running an illegal lottery in Philadelphia (as well as throughout Pennsylvania),” the suit says. Pennsylvania is one of the key swing states where the presidential election between Donald Trump and Kamala Harris will be decided. The election is on a knife-edge in the national polls and also in the crucial battleground states – of which some experts see Pennsylvania as the most important. Krasner’s lawsuit, which names both Musk and America Pac as defendants, comes days after the US Department of Justice warned that the $1m daily sweepstakes could be a violation of federal election law. Musk has been extremely vocal about his endorsement of a potential second Trump presidency. The suit specifies that at an 19 October campaign rally, Musk announced that if a registered voter turned over personal identifying information and signed a petition pledging “support for the constitution”, they would be eligible to be selected randomly for a $1m prize. “That is a lottery,” the suit says. “And it is indisputably an unlawful lottery.” The suit also notes that under Pennsylvania law, all lotteries in that state must be regulated by the state. Despite the justice department’s warning, the Super Pac has continued with the $1m giveaways. It has now handed out nine checks to voters in Pennsylvania, North Carolina, Michigan, Wisconsin, Nevada and Arizona. Don’t miss important US election coverage. Get our free app and sign up for election alerts “The Philadelphia District Attorney is charged with protecting the public from public nuisances and unfair trade practices, including illegal lotteries,” said Krasner in a statement on Monday. “The DA is also charged with protecting the public from interference with the integrity of elections,” he said.