When the grand jury is completed, the court shall appoint one of the number foreman; and the following oath shall be administered by the court, or under its direction, to the jurors: "You solemnly swear that you will diligently inquire into, and true presentment make, of all such matters and things as shall be given you in charge; the State's counsel, your fellows and your own, you shall keep secret, unless required to disclose the same in the course of a judicial proceeding in which the truth or falsity of evidence given in the grand jury room, in a criminal case, shall be under investigation. You shall present no person from envy, hatred or malice; neither shall you leave any person unpresented for love, fear, favor, affection or hope of reward; but you shall present things truly as they come to your knowledge, according to the best of your understanding, so help you God".
http://codes.lp.findlaw.com/txstatutes/CR/1/19/19.34#sthash.1zyKnTAz.dpuf
Jury Nullification?