Confirming media reports, Tesla Inc’s CEO, Elon Musk said, the carmaker’s Nevada factory was a target of a “serious” cybersecurity attack.

According to a report by Teslarati, a news website, Tesla Inc was the unnamed company in a statement issued by the U.S. Department of Justice on Tuesday regarding the arrest of a Russian national in connection with a planned attack on an unidentified company.

“This was a serious attack,” said Musk said in a tweet, in response to the Teslarati article.

In a statement the Justice Department said, Russian national Egor Igorevich Kriuchkov, 27, was arrested and charged with conspiracy to intentionally cause damage to a protected computer by trying to recruit an employee to introduce a malware into a system.

Once installed, the malware, would encrypt the company’s data and on paying a ransom, it would unlock it. Kriuchkov had promised the employee an incentive of $1 million upon introducing the malware into the system, said the DoJ.

According to a complained filed by the FBI’s Las Vegas Field Office, the employee had alerted the FBI, who were successful in thwarting the attack.