A teenager charged with killing his girlfriend's mother and stepfather at their Compton mobile home has an "extremely low" IQ that is consistent with being mentally retarded, an expert testified Tuesday.
Giovanni Gallardo, now 18, had an IQ of 57 when he was evaluated after the killings, placing him within the range of mild to moderate retardation, Dr. Deborah S. Miora, a clinical and forensic neuropsychologist, told the court.
Prosecutors say Gallardo and his girlfriend killed the adults and later went to stores to purchase supplies for a Halloween party while one of the dead victims was in the back of the Jeep they were driving.
Miora, who was called by the defense, said people who score as low as Gallardo are easily influenced and more likely to act without considering the consequences of their behavior.
"They are susceptible to the ideas and influences of others," Miora said. "They want friends. They want to be liked."
Miora testified that the evaluation she conducted determines whether a test subject is trying to achieve a lower score. She said her evaluation showed that Gallardo was not doing so.
She said the Social Security Administration also diagnosed Gallardo as mentally retarded when the agency evaluated him when he was 13.
Gallardo, who was 16 at the time of the October 2011 killings, is being tried as an adult and faces life in prison if he is convicted.
The victims' bodies were found in separate shallow graves. Jose Lara, 51, was handcuffed and his body was covered with a blanket. Gloria Villalta, 58, was bloated from decomposition and her head was wrapped in duct tape.
At the heart of the prosecution's case is a detailed confession Gallardo gave two sheriff's homicide detectives in which he admitted strangling Villalta and hitting Lara with a baseball bat before stabbing him.
A former Santa Monica police homicide investigator called by the defense Tuesday told jurors that detectives should generally avoid leading questions while interviewing suspects and should have only one detective interviewing a juvenile suspect at a time.
Gary Michael Steiner, who retired as a sergeant in 2008, said he would be concerned about the mental ability of a suspect who told him he could not read or write. In Gallardo's case, the teenager told sheriff's detectives he was unable to read or write English.
Under questioning by Los Angeles County Deputy Alternate Public Defender Scott T. Johnson, Steiner said that some suspects might be willing to falsely confess to something without understanding the consequences.
"They can say they did something they didn't do if we don't do our jobs right," Steiner testified.
But during cross-examination, Deputy Dist. Atty. Eric Siddall questioned the suggestion that Gallardo might have given a false confession.
Gallardo gave details about the attack that included the type of baseball bat that was used and led detectives to where the bodies had been buried.
The prosecutor asked Steiner whether that type of information from a suspect amounted to corroboration for a confession. Steiner said it might not necessarily corroborate that the suspect was involved in an actual murder rather than simply show he had knowledge of what occurred after the crime.
The defense wrapped up its case with Gallardo telling Los Angeles County Superior Court Judge Ricardo R. Ocampo that he would not testify. Closing arguments in the trial are expected to begin Wednesday.
Gallardo's girlfriend, Cynthia Alvarez, was convicted earlier this month in both killings.
During her trial, Alvarez, 16, blamed Gallardo for the killings. She claimed she did not want her parents dead but did not seek help because she was afraid of her boyfriend, whom she described as abusive.
A jury deliberated for about three hours before convicting her of first-degree murder.