DNA Laboratory Criminalist Gary Sims is back on the stand to finish up his testimony. The defense team focuses on themes of contamination, planting evidence and police ineptitude. Then another Criminalist at the California Department of Justice, Renee Montgomery, takes the stand. Montgomery testifies in more detail about all the various blood drops and stains recovered from the crime scene and in O.J.'s vehicle and home. Week 18 wraps up with another LAPD criminalist, Collin Yamauchi. While he's on the stand, the jury finally sees the O.J.'s socks that have been discussed throughout much of the blood testing conversations. Another juror gets dismissed. The 38-year-old white juror is replaced by a 71-year-old black woman.