VENTURA (CBS) — Three bells marking the historic El Camino Real, the trail that linked California’s missions, have been stolen last month along Highway 101 in Ventura, authorities said.

The bells, which hang above signs that mark them as part of the El Camino Real trail, stand alongside Highway 101 throughout the state. Thieves have made off with three of the distinctive bells in April, the Ventura County Star reported.

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Mission bells at Seaward Avenue, Telephone Road and Main Street in Ventura have been stolen, Caltrans spokeswoman Kelly Markham told the newspaper.

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The bells are considered state property, she said.

The bells, which cost $2,700 each to make, weigh about 85 pounds and are mounted on 15-foot-tall posts attached to concrete foundations, according to the Star.

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Some bells that have previously been stolen and vandalized were replaced with concrete replicas, but its not known whether the stolen bells  were made of metal or concrete.