Jury Convicts Teen of Slaying Mother, Sister

A jury in Rancho Cucamonga convicted a 17-year-old of second-degree murder Friday for killing his mother and sister.

Paul Yum next will face a sanity hearing to determine whether he knew right from wrong when he shot Ester Yum, 39, and Christine Yum, 9, at their Upland home in June 1999.

San Bernardino Deputy Dist. Atty. Nancy Cooper had told the jury that Yum should be convicted of first-degree murder. But outside court Friday, she said she was satisfied with the verdict.

Defense attorney Angela Oh had argued that Yum should be convicted of voluntary manslaughter. She said years of abuse had left the boy, then 14, suffering post-traumatic stress disorder. A psychiatrist testified for the defense that Yum was in a “dissociative state” during the killings.

The defense never disputed that Yum pointed his father’s single-shot, high-velocity deer rifle at his mother’s head while she slept, then pulled the trigger. He then pulled the bolt and shot his sister in the head as she screamed.

Cooper presented evidence that Yum had told his friends he wanted to kill his parents and had spent at least 25 minutes thinking about his situation before he went into his sister’s bedroom. She argued that those facts made the crime premeditated and thus qualified it as first-degree murder.

But Oh said Yum was under intense pressure to succeed and had been savagely beaten by his father just months before the killings because he was expelled from Claremont’s private preparatory Webb Schools.

She said his position as the firstborn son of a firstborn son in a Korean family meant he had to deal with tremendous expectations, which he could not meet with an average IQ and attention deficit disorder.

He would be beaten when he got bad grades and, on one occasion, was forced to run through his Upland neighborhood naked, Oh said.

On June 11, 1999, Yum found out he had failed a gifted and talented test. He also knew his pending grades from Upland High School would be poor.

That Friday night, he was watching TV when his mother scolded him for not studying. It was their last conversation.

Yum later told police that he just wanted to tell his mother he loved her, but that he also wanted to get away. He had unsuccessfully run away from home the previous summer.

Nancy Kaser-Boyd testified for the defense that Yum had a flashback to the prior beating and entered a state in which he was solely focused on his survival.

He told Kaser-Boyd that he killed his mother, then shot his sister because “she came into my vision.”

Cooper presented evidence that Yum had said he thought his little sister was a brat.

After the killings, he packed up the gun and took thousands of dollars in cash. He got into the family Mercedes and drove to Las Vegas, stopping on the way to dispose of the rifle in the desert.

He went to the Riviera Hotel and Casino, where his father was a well-known high roller, and talked his way into a complimentary room.

He stayed there for two days, until the Korean host at the hotel got in touch with his father, who believed at the time his son had been kidnapped.

Yum told police he had been kidnapped, but detectives didn’t believe his story. He broke down and claimed he had accidentally shot his mother and sister.

Though Yum’s father was subpoenaed, he did not testify or attend the trial. His brother-in-law said he believed he was in South Korea.

The jury found that Yum had “malice aforethought,” which means that he meant to kill when he pulled the trigger, but had not weighed the consequences of his actions beforehand and the crime was not premeditated.

The sanity phase is expected to last about two days, Cooper said. If the jury finds Yum was insane, Judge Gerard Brown will have the option of sentencing him to time in a mental health facility. Otherwise, Yum could face life in prison.