Peterson made cement anchors to weigh his wife's body down in San Francisco Bay. Scott's defense attorney, Mark Geragos, pointed out that no such anchors were found after a search of the floor of San Francisco Bay with sonar equipment accurate enough to locate objects as small as a tin can. However, Geoffrey Baehr, who helped lead over 15 diving expeditions off the Berkeley Marina to search for Laci, testified that thick mud, strong currents, dark waters, and a strong surge can make it "virtually impossible" for such equipment to locate an object, even when the target is known, and that this is why they did not find Laci's body or any anchors. To emphasize this point, Baehr related that when his crew accidentally dropped the underwater sonar device into the water, it took four diving trips to locate it, even though the crew knew precisely where it had landed. Peterson's defense lawyers based their case on the lack of direct evidence and played down the significance of circumstantial evidence. They also questioned whether the investigation was thorough, since Modesto police Detective Mike Hermos admitted he did not check the alibi of a prostitute who was accused of stealing checks from Peterson's mailbox, but Hermos did not indicate that the woman was ever a suspect and prosecutor Dave Harris noted that the checks were stolen after Laci vanished, precluding the woman from involvement in her disappearance. A police community service officer testified that an interview with Peterson had no sound because no batteries had been placed in the tape recorder that was used to record it. Other detectives were called to testify about the extensive search for evidence. The defense suggested the fetal remains were of a full-term infant and theorized that someone kidnapped Laci, held her until she gave birth and then dumped both bodies in the bay. The prosecution's medical experts contended that the baby was not full-term and died at the same time as his mother. Juror Fran Gorman was removed and replaced during deliberations due to misconduct, after she conducted independent research on the case. Jury foreman and attorney Gregory Jackson then requested his own removal, most likely because his fellow jurors wanted to replace him as foreman. Geragos told reporters that Jackson had mentioned threats he received when he requested to be removed from the jury. Jackson was replaced by an alternate. Evidence Among the