The fourth week of James Degorski's capital murder trial began Monday with testimony from members of an aquatic recovery unit who searched the Fox River for the gun authorities say Degorski and his high school pal Juan Luna used in the 1993 slayings of seven workers at a Palatine Brown's Chicken & Pasta.

Authorities acknowledge that the gun Degorski said he and Luna used has never been recovered.

Dive experts Ronald Kurth and Hank Woronka were among the 20 or so divers who participated in the 2002 search for the .38-caliber revolver that police say Degorski told them he threw into the river at the Carpentersville Dam shortly after the murders.

Kurth and Woronka testified that the dive team systematically searched by hand and used metal detectors over three days, but came up empty.

Additionally, civil engineer Nani Bhowmik, an expert on hydrology and hydraulics, testified that water alone could not have moved a gun weighing 1.4 lbs., the estimated weight of a .38-caliber revolver.

Bhowmik's tardy arrival drew a stern admonishment from Cook County Judge Vincent M. Gaughan, who insisted future witnesses arrive on time.

Monday's testimony concluded with the former Northern Illinois Police Crime Lab assistant director whose job was to coordinate the processing of the crime scene.

Charles Principe, now at Abbott Laboratories, said he wasn't notified about the presence of bloody shoe impressions at the foot of the bodies in the refrigeration units and, as a result, didn't have the opportunity to properly photograph the images. The defense appeared to suggest the police mishandled evidence that could have pointed to the real suspect.

As they did earlier in the trial, the prosecution argued the bloody shoe impressions were left by the Cook County Sheriff's officer responsible for removing the bodies from the cooler and freezer. Assistant State's Attorney Linus Kelecius displayed photographs before the bodies were removed, in which no bloody shoe impressions were visible. They appear in photographs when only one victim remains, bolstering the prosecution's claim that authorities left them.

Luna was convicted of the murders in 2007 and sentenced to life in prison. If convicted, Degorski could face the death penalty. Testimony continues Tuesday in Chicago.