La. R.S. 14:121

The offender, under the public bribery, bribery of voters or corrupt influencing articles, who states the facts under oath to the district attorney charged with the prosecution of the offense, and who gives evidence tending to convict any other offender under those articles, may, in the discretion of such district attorney, be granted full immunity from prosecution in respect to the offense reported, except for perjury in giving such testimony.