Digest of Biblical Civil Law

Witnesses were required of the prosecution, but not of the accused (Deut. 19:15; Lev 5:1). This by itself rules out the use of torture because it is requiring a person to become a witness against himself. Only the accuser was forced to testify.
 - Phillip Kayser, Torture: A Biblical Critique, p. 18, http://biblicalblueprints.org/wp-content/uploads/2015/07/Torture.pdf.