LOS ANGELES -- The evidence seemed overwhelming.
A Los Angeles County sheriff's deputy was caught on video stealing trim from an impounded vehicle. Another deputy was captured taking cash after a motorist was shaken down to avoid his car being towed. A third was caught on tape rummaging through an SUV at a tow yard and accused of pilfering designer sunglasses from it.
The case was built around an informant who had worked for the FBI -- a tow truck driver given the code name "Captain America."
The secret recordings he made were enough for local prosecutors to bring corruption charges against three deputies and a sheriff's parking enforcement officer, alleging bribery and theft.
But, last year, when the first case went to court, the star witness dropped a bombshell.
"Captain America," it turned out, wasn't the man sheriff's investigators thought he was.
Albino Mendoza's instincts were to steer clear when an FBI agent approached him in 2012.
The tow truck driver was living in the country illegally and had a criminal history that included convictions for burglary, credit card fraud and other crimes, court and FBI records show.
He had been previously deported back to Mexico and then returned to California to live under a fake name, Damian Castillo. With his new identity, he had begun driving for tow companies in the constellation of small industrial cities that ring Los Angeles to the south. He got married and had three children.
But his wife urged him to work with the FBI, which was investigating allegations of corruption in the county's tow truck industry. Agents, she said, might be able to help him earn legal status in the country in exchange for his cooperation.