Tesla Motors' verified Twitter feed and website seemed to be targeted by hackers Saturday.
The Twitter feed, found under the handle @TeslaMotors, changed to read #Ripprgang during the attack. One particular tweet promised a free Tesla car to people who called an offered phone number.
The Napierville, Illinois, phone number leads to a voice mail greeting that says, "There is no free Tesla," and asks callers not to call back.
Of course CNBC called back. The man who answered says he works in broadcasting in the Chicago area but asked that we not mention his name. He said the phone belongs to his 20-year-old son "who is freaking out" about the exposure.
He said the phone has received hundreds of calls since the tweet went up around 5 p.m.
"We have no idea why we were targeted," he said. "We are working with the FBI to clear it up." He noted that he has not yet been able to connect with anyone at Tesla Motors.
The erroneous tweets were deleted after 6 p.m., ET, although the number appeared again, briefly, on Tesla Motors CEO Elon Musk's personal Twitter feed. Again, the hacked message offered a free Tesla to people who dialed the number.
Tesla's website, which was intermittently returning errors, showed a green background with "spammy" messages everywhere.
Read More Tesla nearly sold to Google?
Tesla Motors did not immediately respond to calls for comment.
Steven Kopack contributed to this report.