MARIPOSA (CBS13) — Authorities nabbed three men accused of stealing an estimated $2 million in precious gems and gold from a Central Valley museum in September.

The robbers were dressed in black and armed with pickaxes as they threatened workers during the September 28 heist at the California Mining and Minerals Museum in Mariposa. They stole various nuggets.

During their attempt to grab a massive 14-pound crystalline gold mass known as the Fricot Nugget, the robbers triggered an alarm. Authorities swarmed the museum, but were unable to catch the thieves.

A joint investigation by CHP, Mariposa County and Placer County Sheriff’s Department s and Sacramento police led detectives to three suspects who may have also committed crimes in Sacramento and Placer Counties.

Edward Rushing III, 40, of El Dorado County, was arrested on multiple crimes, including drug charges. He is believed to be a conspirator in the heist. Matthew Campbell, 43, of Sutter County was arrested for conspiracy to commit robbery. Jonathan Matis, 41, also of Sutter County, was arrested on charges of conspiracy to commit robbery, armed robbery, vehicle theft and vandalism.
The investigation is ongoing and more arrests could be made soon, say officers.

Investigators have not said whether any of the stolen items have been recovered.

This is the second heist this year of rare, valuable metals in Northern California. In February thieves made away with large chunks of gold that were on display in a Siskiyou County courthouse.

(The Associated Press contributed to this story.)