Family members of slain East Palo Alto Police Officer Richard May abruptly left the courtroom in San Mateo Monday afternoon as graphic crime-scene photographs were to be displayed.

Senior Deputy District Attorney Steve Wagstaffe warned May's family and friends, who have been present throughout much of the trial, that exhibits he was about to show would include pictures of the dead officer.

Picture after picture of May under a yellow tarp and at various times exposed to show his injuries were flashed on a screen. A few remaining family members hid their eyes behind their hands and wept, listening to their loved one referred to in the abstract as "the victim," while a county criminologist described each scene in detail.

May was killed on Jan. 7, 2006, after chasing defendant Alberto Alvarez on Weeks Street in East Palo Alto.

Several days of testimony included presentation of the autopsy report, DNA analysis of blood belonging to Alvarez found at the crime scene, the positive identification of a hand print belonging to Alvarez on a white truck in the driveway where May was shot dead and a description of the gunshot wound to the defendant's leg.

Dr. Peter Benson, a forensic pathologist with the the San Mateo County coroner's office told jurors that one shot was lethal to May -- a single shot to the face that into his spinal cord and caused massive bleeding. Benson testified that May literally drowned in his own blood and nothing in modern medicine could have saved him.

May and a teenage Explorer cadet, Marco Marquez, who testified last week, pursued Alvarez after receiving a dispatch call about a fight at a nearby taqueria. Witnesses said Alvarez was in that fight but did not initiate it.

Alvarez's position during a struggle with May could be crucial to the defense. Defense Attorneys Charles Robinson and Eric Liberman claim Alvarez was struck by the officer with a baton and shot in the leg prior to shooting May.

Dr. Linda Lee, an emergency room physician at San Mateo Medical Center, testified Monday morning. Alvarez was shot once in the right thigh and the bullet passed nearly sideways from right to left, exiting just under the buttock at the inner thigh, she said.

Alvarez's right side presumably was facing out when he was shot once by May -- an indication he could not be pointing a gun at May from that angle, Defense Attorney Liberman later said outside the courtroom. "He's a leftie," Liberman said.

Marquez, the teenager who rode along with May, testified last week Alvarez pulled a pistol out of the left side of his jacket with his right hand.

The defense tried further to chip away at testimony of Alvarez as a right-hand shooter who was on the offensive.

Monday afternoon, Katie Lassiter, a forensic evidence specialist with the San Mateo County Sheriff, said she positively identified "100-percent" Alvarez's handprint on a white truck at the crime scene.

Part of the defendant's palm and the tips of four fingers and a sliver of his thumb came up when she dusted for prints. Nearby blood spatters on the truck also belong to Alvarez, she said.

But Lassiter could not say if the prints indicated Alvarez held a weapon in his right hand at the time. On cross-examination, she said she did not find any scratches in the paint where the print was left, which might indicate the presence of a metallic object such as a gun in that hand.

The angles of May's wounds are not consistent with prosecutors' claims that Alvarez fired the fatal shot while May was already knocked to the ground, Defense Attorney Liberman said.

Defense attorneys will seek to exclude evidence on Tuesday that Alvarez's parole officers told him he faced 15 years to life in prison if caught in possession of a firearm under the Federal Triggerlock Law.

Prosecutors will continue testimony on crime-scene evidence by Carlos Jose Jiron, a senior criminalist of the sheriff's forensics lab.

A use-of-force expert will testify on Wednesday about whether May exceeded his duties when he struck Alvarez from behind with a baton.

Prosecutors are expected to wrap up their evidence testimony on Nov. 10, with defense presenting evidence later that day. The jury is expected to deliberate the case by Thanksgiving, Presiding Judge Craig Parsons said.