The Securities and Exchange Commission is looking into a bogus tweet on the Associated Press Twitter account that sent markets into a tailspin on Tuesday, SEC Commissioner Daniel Gallagher said. The FBI is also investigating.

Hackers took control of the AP’s account and sent a false tweet about White House explosions that injured President Obama, which sent a wave of panic selling across financial markets before it became clear it was a hoax.

“You can rest assured we’re looking into it,” Gallagher said.

“I can’t tell you exactly what the facts are at this point or what we’re looking for, but for sure, we want to understand major swings like that, however short it was,” he said.

The FBI “is investigating the matter with the AP and Twitter,” bureau spokeswoman Jenny Shearer said without elaborating.