The NFL said its Twitter feed was hacked Tuesday after a tweet was posted announcing that commissioner Roger Goodell had died.
"We have engaged law enforcement to look into the matter. We are reviewing and strengthening our cyber-security measures," Brian McCarthy, the league's vice president of communications, said in a statement.
The tweet, which was deleted minutes after it was posted, said "We regret to inform our fans that our commissioner, Roger Goodell, has passed away. He was 57. #RIP"
McCarthy earlier confirmed on his owner Twitter page that Goodell "is alive and well."
Shortly after the original tweet about Goodell was deleted from the league's official account, two other tweets the league said didn't come from its office were posted on the page. Those tweets also were deleted.
Goodell made light of the situation later Tuesday, posting a joke on his own Twitter account.
Goodell has been the NFL's commissioner since 2006.