A California police department discovered a secret underground shooting range belonging to a "known gang member", complete with numerous weapons and ammo.

The Fontana Police Department posted pictures of the secret hideaway that they found Thursday night.

Police said officers from the gang unit were serving a search warrant at the residence when they came across a manhole that led to the hideaway. The area also contained thousands of rounds of ammunition and weapons including a "100 round drum for an AR-15 rifle." The evidence was confiscated and multiple suspects were booked, police said. Police did not say how many suspects were taken into custody or specify the gang.

In a press statement, police had a warning for those who wanted to be a gang member, while offering some advice.