1. To adopt measures for preventing the commission of crime;
2. To exclude the offender from all hope of escape;
3. To insure a trial with as little delay as is consistent with the ends of justice;
4. To bring to the investigation of each offense on the trial all the evidence tending to produce conviction or acquittal;
5. To insure a fair and impartial trial; and
6. The certain execution of the sentence of the law when declared.
Acts 1965, 59th Leg., vol. 2, p. 317, ch. 722.