LOS ANGELES (CBS) — Drug violence in Mexico has left many Californians wary of crossing the border after two U.S. citizens were fatally shot on Tuesday.

KNX 1070’s Tom Reopelle reports the two U.S. citizens lived in Tijuana but worked in San Diego.

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The men were waiting in line in a truck when they were gunned down, execution-style.

Victor Clark Alfaro is a resident of Tijuana, but also works in San Diego.

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“It is the first time that we hear in Tijuana that people have been murdered while waiting to cross to the U.S. side,” said Alfaro. “I don’t think this is going to repeat again.”

Investigators found nine millimeter casings used by cartel gunmen near the truck, but it’s not known if the killings were drug-related.

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