While serving a search warrant Thursday night at an alleged gang member's Fontana home, officers uncovered a manhole. When they opened it, they found a ladder under it, police said.
Down below was a cave with a secret shooting range and hideout. Inside, officers discovered a number of weapons and thousands of rounds of ammunition, "including a 100-round drum for an AR-15 rife," Fontana police said Friday on Facebook.
Pictures from the Department
The post featured a warning from the police, along with pictures of a sparse, unfinished underground space.
"We are the champions at Hide n Seek and no manhole will help you," it said.
Interlocking rubber mats lined the ground in one area, with something resembling furniture pads or moving blankets fixed to walls, and a US flag hanging in one corner. Another area had a dirt ground and a wall lined with sandbags.