The museum closed in September after thieves made threats to employees and stole a number of artifacts - worth at least two million dollars.
No cameras are allowed in the museum: "a simple thing that makes it so people can't really do their homework for any type of future robberies or anything like that," California State Parks Supervisor Dan Youngren said.
It's one of several security measures now in place at the California State Mining and Mineral Museum in Mariposa after two masked men armed with a pick-axe ran inside two months ago and forced employees to one side of the building and robbed it of numerous precious gems and minerals.
Security is now so tight not even Action News cameras were allowed inside.
"We've been working in collaboration with the CHP and Mariposa Sheriff's Department on behalf of the investigation," Youngren said.
This after the robbers destroyed several display cases and then ran into the museum vault triggering an alarm and the automatic door to shut.
The suspects reportedly got out before the vault door locked.
"We don't quite have a dollar amount yet," Youngren said.
The museum's most valuable piece, the Fricot Nugget was not taken, but for now it will remain behind closed doors, that's because park officials have closed the vault to the public until their investigation is complete and necessary repairs have been made.
It's not the only museum in town taking extra precautions to keep employees and it's exhibits safe.
Reporter: "are you doing anything differently?"
Ellie Fournier, Mariposa Museum Tour Director: "Yes, as a matter of fact a couple of our board members are researching security equipment right now for our museum, panic buttons for behind the counter and video surveillance and such."
Curators at the mariposa museum and history center are on high alert until the suspects in the neighboring museum heist are caught.
"Yes, there are a few things that aren't on display that's pending the investigation, but there's plenty more items of interest people should come out and take a look at," Youngren said.
The museum is now open Thursday through Sunday from 10 a.m. to 4 p.m.