Montebello Man Sentenced to Death for Gateway Triple Murder

A Montebello man who murdered a former girlfriend, her brother and father during an early morning shooting rampage in Hawaiian Gardens 5 1/2 years ago was sentenced to death Friday.

Joseph Mercado, 32, was convicted Nov. 12 of first-degree murder for the May 6, 2010, killings of his ex-girlfriend, Serena Tarin, 23, her father, Alfredo Tarin, 53, and 19-year-old brother, Alfred “A.D.” Tarin. The same jury recommended a week later that he be sentenced to death.

He was also convicted of three counts of attempted murder and one count each of first-degree burglary with a person present, shooting at an inhabited dwelling, child abuse and arson of an inhabited structure, and jurors found true the special circumstance allegations of multiple murders, murder while lying in wait and arson during the commission of a murder.

He was acquitted of one count of assault with a machine gun or assault rifle on a peace officer.

During the sentencing hearing in Norwalk, Superior Court Judge Raul Sahagun denied a motion to reduce the jury’s recommendation to life in prison without parole.

At the start of the trial’s penalty phase, jurors heard recordings of frantic 911 calls made by Serena Tarin and her younger brother shortly before they were killed.

“I need an officer here. My ex-boyfriend’s here and he’s not welcome here ... He has no business being here ... I think he’s trying to get inside,” she reported in the call made at 3:41 a.m.

“Oh my God, oh my God, oh my God,’ she said frantically after popping sounds can be heard in the background. “Please hurry. Oh my God, please hurry.”

The 911 operator asked, “What was that noise?’ with the young woman responding,”I don’t know” and later informing them of Mercado’s name and age when asked his identity.

She is later heard saying, “Joseph, don’t do this, please don’t do this ... the baby,” referring to their child.

As the recording was being played in court, Mercado sat with his hands covering his face and appeared to be crying after jurors heard the recording.

The panel also heard a recording of a 911 call made by the woman’s brother shortly before he was killed.

“You’ll hear A.D. take his last breath,” Deputy District Attorney Robert Villa told jurors.

“Please hurry, please help, please!’ the 19-year-old could be heard pleading in the recorded 911 call in which he reported gunshots.

A 911 operator could later be heard repeatedly asking if he was OK as a woman screamed in the background.

Authorities said shortly after the crime that Mercado was involved in a child custody dispute with his ex-girlfriend and tried to set the home on fire.

Mercado then broke into the back of the home and opened fire with an assault rifle, killing the mother of his young son and the other two victims. Two others, including Tarin’s mother, were wounded.

About a half-dozen other family members escaped, with some hiding on the roof.

The couple’s son was later adopted by Serena Tarin’s sister and her husband.

Mercado was shot by a Los Angeles County sheriff’s deputy as he emerged from the home that morning.

--City News Service, photo courtesy of the LASD