Tesla Motors is going after an oil industry executive after he allegedly tried to pose as the automaker’s outspoken co-founder and CEO Elon Musk.

According to Bloomberg, Tesla tsla says the chief financial officer of Quest Integrity Group penned an email to the Palo Alto automaker’s CFO last month, using a fake email address. Quest is a Seattle-based oil pipeline services provider.

The electric vehicle maker is now accusing the Quest CFO, Todd Katz, of seeking “highly confidential and proprietary Tesla business information,” according to the complaint.

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Tesla says it all started when the firm’s CFO Jason Wheeler got a suspicious email on Aug. 3, just after the company had announced its earnings for the second quarter.

Using the email address “elontesla@yahoo.com,” Katz allegedly wrote the following to Wheeler:

“why you so cautious w Q3/4 gm guidance on call? also what are your thoughts on disclosing M3 res#? Pros/cons from ir pov? what is your best guess as to where we actually come in on q3/4 deliverables. honest guess? no bs. thx 4 hard work prepping 4 today

em”

Musk has reportedly used a similar email handle in the past. Wheeler, of course, didn’t buy it, launching an internal investigation to track down who was behind the intrusion.

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After supposedly linking the account to Katz, Tesla filed a complaint in the Superior Court of Santa Clara County, also stating the involvement of 10 other unnamed individuals, Forbes reported. Tesla suspects the email may have been an attempt by its oil adversaries to lobby against its renewable energy efforts, according to the filing.

“In recent years, oil companies have spent billions of dollars on legislative efforts and campaigns aimed at blocking progress toward electric cars and other sustainable energy solutions in the United States and abroad,” Tesla said in its complaint.

John Hueston, the attorney representing Tesla, said, “[T]he point of this action is that this was perceived as an effort to gain inside information, non-public information.”

“Although it was caught here, Tesla is worried about this happening in some other form,” he added. “This could have resulted in highly valuable information being improperly disclosed.”

Tesla is reportedly seeking to recoup the money it spent on its investigation, as well as reimbursement of legal fees.