The American criminal justice system prides itself on convicting only those who have been proven guilty beyond a reasonable doubt, but much of admissible forensic evidence on which juries base their determination of guilt or innocence has not been rigorously tested or peer reviewed. Sometimes, it is contaminated, inaccurate, or unreliable, and occasionally, forensic experts are mistaken in their analysis, exaggerate their conclusions, or provide misleading testimony. In Forensics IV: Guilty Until Proven Innocent, I discuss how flaws in forensic evidence, including fingerprint, firearm, DNA, hair, bite-mark, and bloodstain pattern analyses, as well as limitations in eyewitness identification, overstated conclusions by forensic experts, scientific fraud at the FBI and state forensic crime laboratories, and police and prosecutorial misconduct result in innocent people being found guilty of crimes they did not commit. Once wrongfully incarcerated, it is almost certain the process of postconviction relief toward exoneration will be long and arduous, unlike defendants who are guaranteed a speedy trial. Some of the wrongfully convicted people I reviewed include Amanda Knox, wrongfully incarcerated in Italy for murdering her housemate based on false DNA analysis; Ronald Cotton, misidentified and convicted of rape, only to be exonerated after nearly eleven years and team up with the victim to lecture about faulty eyewitness identification; Brandon Mayfield, an Oregon attorney wrongly accused of being an Islamic terrorist involved in the 2004 train bombing in Madrid, Spain, based on faulty fingerprint identification; Kirk Odom, wrongfully imprisoned for more than twenty-one years as a result of false microscopic hair analysis; Keith Harward, wrongfully convicted of rape and murder based on overstated bite-mark comparison analysis; Julie Rea and David Camm, found guilty of killing her son and his wife and two children, respectively, based on inaccurate bloodstain pattern analysis; Patrick Pursley, wrongfully convicted of murder due to firearm misidentification; Kirk Bloodsworth, the first death row inmate to be exonerated with DNA evidence; and five men wrongfully incarcerated because of false microscopic hair analysis; among others.