Expert Testifies : Tape Tells Timing of Penn’s Shots

Times Staff Writer

A forensic voice expert testified Monday that his analysis of a police emergency tape indicates that less than one second elapsed between the time Sagon Penn fatally shot San Diego Police Agent Thomas Riggs and wounded civilian Sara Pina-Ruiz.

The sequence of shots fired is considered crucial in the police murder trial because witnesses have given conflicting accounts of what took place March 31, 1985, when Penn killed Riggs and wounded Agent Donovan Jacobs and Pina-Ruiz, who was a passenger in Riggs’ police car.

The prosecution’s initial witness, Junius Holmes, testified last month that after Penn shot Riggs three times, he turned to Pina-Ruiz and said “You’re a witness” before shooting at her twice through the driver’s side window.

But on Monday another prosecution witness, Craig Melvin, a police acoustics analysis expert, appeared to bolster defense claims that Penn did not have enough time to say anything to Pina-Ruiz.


Melvin, an audio tape investigator for the Los Angeles County Sheriff’s Department, said he analyzed a police emergency tape more than 200 times in an attempt to produce a transcript and learn the precise sequence of shots fired. (The shots can be heard in the background when a resident called the 911 number to report a case of “police brutality.”)

By detecting impulse sounds on the tape with advanced audio equipment, Melvin said he believes that six shots were fired in a total of 5.7 seconds. Melvin’s findings are similar to an independent defense study of the tapes which reveals that the six shots were discharged in less than six seconds, according to Penn’s attorney, Milton Silverman.

Melvin’s testimony, combined with other evidence, shows that Penn shot Jacobs once in the neck 9.75 seconds after a nearby resident called police dispatchers to report a case of “police brutality.” Then, 2.1 seconds later, Penn stood and shot Riggs three times in a span of 2.25 seconds.

Within eight-tenths of a second, Penn turned around and shot Pina-Ruiz twice as she sat in the front passenger seat of the police car.


Penn, 24, is charged with one count of murder and three counts of attempted murder. Penn claims that both officers provoked him by repeatedly beating him with batons.

Jacobs is expected to take the stand today, followed by Pina-Ruiz.

Cedric Gregory, 18, testified Monday that he was riding in the back of a white pickup truck driven by Penn when the vehicle was stopped by police in the Southeast San Diego neighborhood of Encanto.

Gregory said that after Penn produced identification and asked why he had been stopped, Jacobs grabbed Penn and began beating him with his night stick. The violent struggle then moved down a driveway where Penn was knocked down and Jacobs pounced on top of him, Gregory said.


He said that Jacobs used racial remarks and told Penn, “You think you’re bad, don’t you?”

Gregory added: "(Jacobs) was hitting him in the head with his fists. When (Jacobs) was finished . . . (Riggs) hit him on the head with his night stick.”

Prosecutor Michael Carpenter asked Gregory what Penn was doing on the ground while Jacobs was on top of him. Gregory replied, “He was getting beat.”

Carpenter has attempted to show that Penn, who is proficient in the martial arts, exchanged blows with the two officers. But several times Gregory described all of Penn’s blows as “defensive.”


Gregory told Silverman under cross-examination that when he saw Pina-Ruiz in Riggs’ patrol car, he assumed she was a “lady police officer.”

Silverman has argued that Penn mistook Pina-Ruiz, who had accompanied Riggs under the police ride-along program, for a police officer when he shot her.