By MICHAEL G. MOONEY and TY PHILLIPS
BEE STAFF WRITERS
(Published: Wednesday, October 27, 1999)

   After nearly seven weeks of testimony, prosecutors in the Douglas Mouser murder trial finally called to the witness stand the only person who could say the dead body of Genna Lyn Gamble had been inside her stepfather's car.

   But jurors heard nothing about that Tuesday.

   Instead, they heard a daylong discussion of Gary Robertson's expert credentials in a field of study so obscure few people even know it exists -- the science of photogrammetry. Simply put, a photogrammetrist extracts measurements or data from images such as still photographs.

   Mouser, a computer expert who once held a top-secret security clearance at Lawrence Livermore National Laboratory, is accused of strangling his 14-year- old stepdaughter in October 1995 and then dumping her nude body in a remote area near Waterford.

   Over the objections of defense attorney Richard Herman, Stanislaus County Superior Court Judge Donald E. Shaver on Tuesday allowed the prosecution to conduct an exhaustive discussion of Robertson's qualifications, complete with a slide show featuring a wide array of projects the Canadian has worked on -- everything from the space shuttle and F-18 fighter jets to the construction of dams.

   Once the prosecution completed its presentation, Shaver allowed Herman to challenge the expert's credentials.

   It is Robertson's use of photogrammetry in murder investigations that has raised Herman's ire.

   Photogrammetry has been used for years in aerial surveying, as well as investigations of automobile accidents and plane crashes. Robertson, through the use of digital technology, computers and specialized software he developed, has adapted photogrammetry for use in criminal investigations.

   Herman and Robertson first clashed in February 1998, during Mouser's preliminary hearing. That appearance marked the first time Robertson had testified as an expert in a criminal proceeding in the United States.

   In the months leading up to Mouser's trial, Herman unsuccessfully tried to keep Robertson from testifying at all.

   After analyzing autopsy photographs and other photos, Robertson said he was able to match marks and indentations on Gamble's right leg with a carpet pattern and seat-belt buckle in the back seat of the Mouser's Honda Civic.

   Other experts who testified at the hearing said the marks and indentations occurred after Gamble was dead.

   Herman began questioning Robertson late Tuesday afternoon, challenging the expert witness's education and field of expertise. He was unable to rattle Robertson, however, and several times Judge Shaver told him to stop arguing with the witness.

   The defense attorney's best moment came when he asked Robertson to define forensic science. Robertson replied, "the study of forensics."

   "OK," Herman said, "what is the study of forensics."

   "I can't answer that," Robertson said, after a long pause.

   During his testimony, Robertson expanded on concepts such as repeatability and error analysis and explained the differences between precision and accuracy. At one point while he was talking, Mouser and Herman took turns briefly playing solitaire on a portable computer.

   "I'm probably going to put a whole bunch of people to sleep here," Robertson said later, drawing laughter from jury members overloaded with complicated information.

   Before the afternoon session began, Shaver gave the jury some bad yet somewhat expected news. The target date for jury deliberations was moved back several more weeks -- from a few days before Thanksgiving to Dec. 10.

   One juror pumped his fist and said, "all right" in mock celebration. The others laughed.