Expert witnesses: writ of habeas corpus.

Existing law allows a person who is unlawfully imprisoned or restrained of their liberty to prosecute a writ of habeas corpus to inquire into the cause of their imprisonment or restraint. Existing law allows a writ of habeas corpus to be prosecuted on the basis of false evidence that is substantially material or probative to the issue of guilt or punishment that was introduced at trial. Existing law defines false evidence for these purposes as including the opinions of experts that have been repudiated by the expert or that have been undermined by later scientific research or technological advances. This bill would additionally allow a person to prosecute a writ of habeas corpus if a significant dispute has emerged or further developed in the petitioner's favor regarding expert medical, scientific, or forensic testimony that was introduced at trial and contributed to the conviction, such that it would have more likely than not changed the outcome at trial, as specified. The bill would also expand the definition of false evidence to include the opinions of experts that are undermined by the state of scientific knowledge. This bill would incorporate additional changes to Section 1473 of the Penal Code proposed by AB 256 to be operative only if this bill and AB 256 are enacted and this bill is enacted last.