Thankfully, no. The United States Supreme Court ruled in Brady v. Maryland, 373 U.S. 83 (1963) that Constitutional rights are violated if a prosecutor withholds evidence that is favorable to the innocence of the person accused. To withhold such evidence has been termed a “Brady violation.” A Brady violation could result in a new trial for someone who had been found guilty.
California has gone a step further to prevent Brady violations. Last Friday, Governor Jerry Brown signed a bill into law that would subject a prosecutor to a felony and up to three years in prison for altering or intentionally withholding evidence that could exonerate a defendant. Previously, a prosecutor was subject only to a misdemeanor. This bill was inspired by controversies surrounding the Orange County District Attorney’s Office as well as an illegal jailhouse-informant program.