A punch to the gut. That's how the president of a nonprofit working to revive a historic outdoor theater describes a debilitating break-in.

The Starlight Bowl amphitheater in Balboa Park was broken into Saturday evening. Thieves stole up to $50,000 worth of equipment bringing a 5-year-long effort to restore the theater to its knees, according to Steve Stopper President of Save Starlight.

"I got a call from the city at about 5 p.m. and they said that the doors were wide open and that the rangers were already there,” explained Stopper.

Police believe the suspects busted through the metal doors and spent hours sweeping the place, stealing valuable signed guitars before heading upstairs.

Stopper had just turned a room upstairs into a working television station to allow for a student broadcast overlooking the amphitheater. That's where most of the equipment was stolen.

“I can list what guitars were stolen; some were signed by the B-52s, Tom Petty, and Styx,” Stopper said.

NBC 7

The signatures took years to collect and they were meant for auction to advance the restoration of the Starlight Bowl.

Starlight was still recovering after a eucalyptus tree collapsed on part of the building, damaging the ticket and concession building.

"This has been a multiple year effort that just went down the drain,” said Stopper. "This is really a railroading moment. I don't know what to do. We’ll have to figure it out."

The thieves even had enough time to eat during the heist.

"There was some food left out in a bowl so they had enough time to eat it during the theft, and snacks we had stored," explained Stopper. "They must have been here a very long time."

Stopper has a donation page that was set up when the tree collapsed.

If anyone has any information you can contact the San Diego Police Department or Crime Stoppers at (888) 580-8477.