Federal agents and Honolulu police executed a search warrant at the Thai House restaurant at the Market City Shopping Center Monday night, according to FBI agent Tom Simon.
The warrant was part of an investigation into an alleged illegal gambling investigation.
No arrests were made.
Customers inside the restaurant were taken by surprise with the search that started at around 8 p.m.
"At least 30 FBI guys were in there by the time I had to leave. They kept walking in there," said witness Kala'e Camarillo. "They made me get out immediately and they closed all the blinds so no one could see inside. The whole place was packed with FBI guys."
Another witness told KITV that upon asking customers in the restaurant to leave, FBI agents then ordered the employees to get on the ground.