Over a year after a Northern California man was charged with a DUI, those charges have been dropped, as prosecutors said that they couldn't prove he was under the influence of anything stronger than caffeine.

It was August, 2015 when 36-year-old Fairfield, California resident Joseph Schwab was pulled over by an Alcohol Beverage Control agent for “weaving in and out of traffic almost causing several collisions," KRCA reports. Believing Schwab to be high on more than life, the agent "conducted several field sobriety tests and found Schwab’s pupils were dilated." Prosecutors later said that he “seemed very amped up, very agitated, very combative, and she thought he was under the influence of something.”

A search of Schwab's car uncovered some powered substances, revealed to be perfectly legal workout supplements. And when he took a blood test following his arrest, it showed no trace of booze, coke, meth, THC, opiates, oxycodone and all the other drugs you might think of when you think of an impaired driver. The only hit it got: Caffeine.

[Disclosure: I'm drinking coffee as I type these very words.]

Despite these less-than-damning results, Solano County District Attorney Krishna Abrams said at the time that she was committed to prosecuting Schwab for a DUI regardless, even admitting “This is a case without a blood result, so it makes it a very difficult challenge to prove in court."

That challenge was apparently insurmountable, as this week Abrams dropped the charges against Schwab, saying via press release that "After further consideration, without a confirmatory test of the specific drug in the defendant's system that impaired his ability to drive, we do not believe we can prove the charge beyond a reasonable doubt."

According to KCRA, however, Abrams still maintains that "some drug other than caffeine was in Schwab's system, but that testing didn't reveal it," and notes that "Synthetic cannabinoids like spice, performance enhancing drugs like steroids, and designer stimulants like bath salts are rarely tested in DUI blood tests."

"Do we wish that it could test for more drugs?" Abrams said to KCRA. "Absolutely, because then we would know what was in his system."

Schwab continues to dispute her insinuation, saying that he is "100 percent confident that I was not under the influence of anything" when he was pulled over. According to Solano County officials, Schwab still faces misdemeanor charges of reckless driving for the behavior his arresting officer alleges she witnessed on the road. A call to his attorney to see if they would fight those charges as well has not been returned as of publication time.

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