PART ONE
GENERAL PROVISIONS
CHAPTER X
EXAMINATION OF THE ACCUSED
Section 136a.
[Prohibited Methods of Examination]
(1) The accused’s freedom to make up his mind and to manifest his will shall not be impaired by ill-treatment, induced fatigue, physical interference, administration of drugs, torment, deception or hypnosis. Coercion may be used only as far as this is permitted by criminal procedure law. Threatening the accused with measures not permitted under its provisions or holding out the prospect of an advantage not envisaged by statute shall be prohibited.
Fair trial standards
Rights during investigation - arbitrary arrest or detention and deprivation of liberty
EDIT.