Members of a SWAT team raided the Myrtle Beach Hells Angels clubhouse, off Highway 814 in Horry County Monday night.
NewsChannel 15 received phone calls into the newsroom from people who heard explosions.
Scott Rutherford, with the Horry County Police Department, said the noise came from concussion grenades that were detonated as agents made their way into the club.
Rutherford tells NewsChannel 15 that Monday night's raid is part of an ongoing investigation by Horry County Police, Myrtle Beach Police, the State Law Enforcement Division, and the Greenville County Sheriff's Office.
As of 10:30 p.m on Monday, no one had been arrested and police say no one was hurt.
Authorities would not say what the investigation concerns, but said it is not drug related.