The worker reportedly misheard a recorded message that was part of an unscheduled drill.

The emergency worker responsible for sending a false missile alert to people in Hawaii earlier this month actually believed there was an incoming ballistic missile, The Washington Post reports.

The worker sent the public safety alert after mishearing a recorded message that was part of an unscheduled drill, according to a preliminary investigation conducted by the Federal Communications Commission.

The state worker who sent the alert, whose name has not been released by officials, has refused to cooperate with the agency’s investigation, Lisa Fowlkes, head of the FCC’s Public Safety & Homeland Security Bureau, said last week during a Senate Commerce Committee hearing.

“We are disappointed … that one key employee, the person who transmitted the false alert, is refusing to cooperate with our investigation,” Fowlkes said. “We hope that person will reconsider.”

A representative for the Hawaii Emergency Management Agency told HuffPost that the employee wasn’t cooperating with the state’s investigation either.

An estimated 1.2 million people received the alert on Jan. 13. People in the state were sent into a frenzy, and many sought shelter.

Many officials knew the alert was a mistake immediately, but it took nearly 40 minutes for the state’s emergency agency to send out a second alert letting people know the original had been a false alarm.

The governor reportedly knew of the error two minutes after the alert was sent out, but it took him 15 minutes to tweet about the false alarm because he didn’t know his Twitter password.

The Hawaii Emergency Management Agency responded to the incident by saying it would implement new actions to prevent such an error in the future, including requiring two people to sign off on alerts and installing a “cancellation command” that can be triggered within seconds.

Source: Huffington Post, TIME