Fat Boy Drive-In reopened Monday following a bomb threat made to the restaurant on Sunday afternoon.

According to Brunswick Police Chief Scott Stewart, the threat was made when a caller told a restaurant employee there was a bomb inside. Stewart said that the investigation is ongoing and no other updates are available at this time.

According to Stewart, the threat falls under a Class C crime, a felony that is punishable by up to 5 years incarceration and a $5,000 fine.

“What started out to be a great day at Fat Boy ended abruptly due to a bomb scare committed by a coward,” the restaurant wrote in a social media post. “We cannot be more thankful that all of our employees and patrons are safe and unharmed.”

Police said they were alerted to the situation at 4:30 p.m. Sunday and that when officers arrived, staff and customers had already evacuated.

The parking lot where the carside service takes place was also evacuated. Maine State Police explosives detection’s K9 unit found no explosives or explosive devices on the property or inside the restaurant. No injuries were reported.

According to the same post, after the restaurant was cleared by police on Sunday, Fat Boy closed for the remainder of the day. On Monday, Fat Boy reopened at 11 a.m.

“We are very saddened by the fearful act that was made yesterday leaving employees and community members questioning their security,” the post continued.

Fat Boy declined a request for further comment.

The restaurant, which has maintained a unique 1950s-style drive-in service, is staple of Brunswick and sits across from the former Naval Air Station. Fat Boy first opened in 1955.