On Friday, authorities in Houston raided the Paradise Day & Night Bingo Hall based on tips that the unassuming hole-in-the-wall was actually a haven for hardcore criminals.

What they found was shocking to say the least.

Inside was a stash of guns, cash, body armor and and an insane amount of ammunition.

"(It was) full of all caliber, including 50 caliber,” said Harris County District Attorney Devon Anderson. “I mean, when do you see that?"

The bust followed a year long undercover operation into the bingo hall alongside more than 200 underground game rooms across Harris County.

In all, 12 people were arrested including owners Robert Jones and Fred Kennedy.  They are charged with engaging in organized criminal activity.

In addition to the weapons, authorities seized $87,000 in cash.

The bingo hall, which is located near Hobby Airport, resembled a "doomsday shelter" cops told reporters on Friday.

Prosecutors also say that Kennedy and Jones were using family-owned ATMs to launder over $15 million in illegal earnings from the bingo parlor.

For their part, the accused's attorneys deny the claims.

"It's ridiculous is what it is. It's a legitimate bingo hall,” said Stephen St. Mark, defense attorney. “They're running a state-licensed bingo operation."

Nevertheless, Harris County Sheriff's Office Lt. Ruben Diaz says what they found was startling.  He says that there was no reasonable justification for having this amount of weaponry.

“Enough, what I would consider, to start a small war,” Diaz said during the Friday press conference. “This is one of largest seizures of guns I’ve seen in one particular spot.”

Investigators believe the guns were purchased with money from the gambling operation and customers may not have known about the alleged connections to organized crime.

"So far we have seized hundreds of thousands of dollars, and as we look more closely at bank accounts we anticipate seizing more," said Anderson. "At this one location here, we found several safes and tens of thousands of dollars and some of the safes were very difficult to find. We discovered hidden rooms and a bunker there is a huge walk in safe that belongs in a bank."