RELATED: San Quentin inmate who walked away from prison spotted in Central Coast town
Police across California are on the lookout for the 21-year-old escaped convict who may be driving a 2011 silver Toyota RAV4 with California license plate number 6STZ502.
He was serving a five year sentence for using a deadly weapon during a carjacking in Los Angeles County.
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Prison officials still have not explained how Mendoza escaped, only saying: "Mendoza was assigned to work outside the security perimeter on a work crew, he took advantage of that and walked away."
A source tells ABC7 News that the 21-year-old may have been cleaning a sewage pumping station not far from San Quentin's West Gate.
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SKY7 was over the Area where wastewater is pumped out to the Central Marin sanitation agency, a half mile away. GM Jason Dow says it's common for inmates to maintain the pumping station.
"This fellow may be one of those," he said. "And you know, if he was, he was probably one of the fellows that was cleaning the racks out of the influent channels of the pump station."