To commence the prosecution, all he needs is probable cause that the offense was committed. The standard is that there is such evidence (and statements by witnesses are evidence) that a reasonable person is more likely to believe the offense committed than not. This is far less than what is needed to convict at a trial.
Not exactly. The more likely than not standard applies to most civil lawsuits. It does not apply to the concept of probable cause. There is no particular percentage standard applied to probable cause. The Ninth Circuit Court of Appeals, which is the federal appeals circuit that includes California, defines probable cause as follows:
“Probable cause to arrest exists when officers have knowledge or reasonably trustworthy information sufficient to lead a person of reasonable caution to believe that an offense has been or is being committed by the person being arrested.” United States v. Lopez, 482 F.3d 1067, 1072 (9th Cir.2007) (citing Beck v. Ohio, 379 U.S. 89, 91, 85 S.Ct. 223, 13 L.Ed.2d 142 (1964)). “The probable-cause standard is incapable of precise definition or quantification into percentages because it deals with probabilities and depends on the totality of the circumstances.” Maryland v. Pringle, 540 U.S. 366, 371, 124 S.Ct. 795, 157 L.Ed.2d 769 (2003). Indeed, “probable cause is a fluid concept-turning on the assessment of probabilities in particular factual contexts-not readily, or even usefully, reduced to a neat set of legal rules.” Illinois v. Gates, 462 U.S. 213, 232, 103 S.Ct. 2317, 76 L.Ed.2d 527 (1983).
Rodis v. City, Cty. of San Francisco, 558 F.3d 964, 969 (9th Cir. 2009). As you can see, the Court quoted the U.S. Supreme Court in rejecting the notion of any "precise definition or quantification into percentages" for probable cause.
Your son needs an attorney big time if he is being prosecuted.
Absolutely agree with that.