No person shall be excused from attending and testifying or from producing books, papers and documents before any court having jurisdiction of the offenses defined in this chapter, upon the ground, or for the reason that the testimony or evidence, documentary or otherwise, required of him may tend to incriminate him or subject him to a penalty or forfeiture. But no person shall be prosecuted or subjected to any penalty or forfeiture on account of any prosecution, matter or thing concerning which he may produce evidence, documentary or otherwise, before any court as aforesaid. (Prior code §12-76)