Thieves steal golden nuggets from a California museum

Police in California are investigating a series of brazen robberies.

San Francisco police say thieves drove a stolen SUV into the Wells Fargo Museum in the city's financial district and stole golden nuggets.

The three masked-men got out of the vehicle, held a security guard at gunpoint and made off with the gold nuggets from a display case. They escaped in a car and then vanished.

Officials say it's the fifth robbery since November where thieves have used a car as a battering ram.

Jewelers say the gold nuggets are rare and could be worth up to $50,000.