A private citizen group of taxpayers had taxpayer standing under CCP 526a to sue the District Attorney seeking an injunction to stop his office’s confidential informant program, the principal aim of which was to secure confessions from criminal defendants in violation of their constitutional rights. The suit was brought by taxpayers to enjoin waste of public funds on an illegal program. The suit was not precluded by CC 3369 barring injunctions to enforce a penal law–that deals with injunctions to prevent crimes by potential defendants, not illegal conduct by prosecutors. Allowing the suit will not interfere with on-going criminal suits brought by the District Attorney, even though individual defendants may raise the same issues in their defense. The taxpayer suit did not threaten a collateral attack on any criminal case’s judgment since it sought only prospective relief stopping the confidential informant program, not relief for any criminal defendant(s). Plaintiff also had public interest standing to seek a writ of mandate directing the District Attorney to discontinue the program.