SAN MATEO (CBS SF) -- From surveillance cameras to cellphones to body cams -- we're being watched everywhere we go. All that video evidence has revolutionized the way crimes are investigated and prosecuted.
Take for example graphic dashboard video of a woman stabbing a San Mateo cab driver in the neck. The entire attack was captured in all its horrific detail by the cab's surveillance camera.
The driver survived the attack but the video was slam dunk evidence for San Mateo County Prosecutor Aaron Fitzgerald. He called it the smoking gun.
"We as prosecutors … try to paint a picture to the jury -- video shows it and reveals it," said Fitzgerald.
The case never went to trial. The woman pled guilty.
Like DNA, tell-tale video is a game changer. San Mateo County District Attorney Steve Wagstaffe says it's now standard procedure.
"[We] Check the neighborhood to find out if anyone has a surveillance camera," said Wagstaffe. "The number of cases we've come up with good strong evidence is in the hundreds and hundreds."
Cameras at a San Jose luxury car dealer tracked a band of thieves breaking in, taking key fobs and helping themselves to five luxury cars on the lot.
Eight Mercedes were stolen from a Belmont car dealer in a similar way. Police have recovered 6 of the cars, and video has already lead to 3 arrests.
Cameras are in neighborhoods, on cell phones, and dash cams. With police checking for video evidence, it's getting harder and harder to be a bad guy.
But could a judge, or a defense attorney argue that citizens have reasonable expectation of privacy and police are violating that privacy with a hidden camera?
"The bottom line is in most of these cases it's not the police who are doing it [recording], and the 4th Amendment only applies to governmental action," said Wagstaffe. "If someone has a surveillance camera in their home and catches something going on next door, or something like that, that's not subject to suppression."
Video can also help a defendant. In the case of the disturbing stabbing attack on the taxi driver, after the driver escaped she climbed into the front seat and drove off.
"She turned the radio on and was actually playing music, and if I remember correctly, one of the songs that came on the radio was 'Freak Out,'" said Fitzgerald. "She was be-bopping, singing along with the music."
Her defense argued that was a sign of mental illness. She was sent to a state hospital, instead of a state prison.
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