News Releases

November 12, 2015: Montebello Man Convicted of Killing Ex-Girlfriend and her Family

Sarah Ardalani, Public Information Officer
(213) 257-2000

A 31-year-old man was convicted today of capital murder for a triple-killing that occurred in Hawaiian Gardens in 2010, the Los Angeles County District Attorney’s Office announced.

The jury deliberated for two days before finding Joseph Mercado guilty of 10 felony counts in case BA382849: three counts of first-degree murder, three counts of attempted murder, and one count each of first-degree burglary, shooting at an inhabited dwelling, arson of an inhabited structure or property and child abuse.

Jurors also found true special circumstance allegations of multiple murders, lying in wait and engaging in arson. Additionally, jurors found true special allegations that the defendant personally inflicted great bodily injury and personally and intentionally discharged a firearm during the commission of the crime.

The penalty phase of the trial to determine whether Mercado will be sentenced to death or life in prison without the possibility of parole is scheduled to begin tomorrow, Nov. 13 in Department D of the Los Angeles County Superior Court, Norwalk Branch.

Deputy District Attorneys Robert Villa and Franco A. Baratta co-prosecuted the case.

According to prosecutors, on May 6, 2010, Mercado set fire to his ex-girlfriend’s home in Hawaiian Gardens. Serena Tarin and her family were inside the residence, prosecutors said.

Mercado then broke into the back of the home and opened fire with an AK-47 rifle, prosecutors added.

Serena Tarin, the mother of Mercado's infant son, and her brother and their father were killed. Two others were wounded, one critically.

Following the shooting, as the defendant exited the house, he was shot by a sheriff's deputy and arrested.

The case was investigated by the Los Angeles County Sheriff’s Department.