ALHAMBRA (CBSLA) — LA County Sheriff Alex Villanueva said he had “a somber, sad announcement” Wednesday when he told the media that deputy Joseph Gilbert Solano died Wednesday afternoon.

Solano was shot in the back of the head Monday evening while ordering food at a Jack in the Box in Alhambra.

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Villanueva said Solano died “despite a valiant effort” by the medical staff at the hospital. “They worked diligently around the clock for the last two days trying to do a miracle but, unfortunately, that didn’t come to pass.”

Officials believe the attack was random. Solano was off-duty at the time of the shooting and in plain clothes.

A suspect in his murder was taken into custody Tuesday morning in Long Beach.

Authorities believe the same man may also be responsible for a killing in downtown Los Angeles which occurred about one hour prior to the deputy’s shooting.

At an emotional press conference Wednesday outside County-USC Medical Center Solano’s son, step-daughter and longtime girlfriend all spoke. choking back tears.

His son Matthew thanked “everyone who has had my dad in their prayers.”

He said, “Unfortunately, we have lost him. He was a really good dad. So…I thank all the law enforcement agencies that have been a part of this and thank you to everyone that has had him in their prayers. Continue to pray for him and my family, please. Thank you.”

Matthew, Jessica — his step-sister — and the victim’s girlfriend — named Juliana —  all held hands and stood behind Villanueva his voice also breaking.

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Said Jessica, “Joseph Gilbert Solano was my step-father. He has been in my life for over 11 years. And not only did I lose a father figure but a best friend. But I would like to thank everyone who has supported us, sent us prayers and the whole entire law enforcement. Everyone has been more than supportive and helped us with whatever we needed.”

Deputy Joseph Solano’s body arrives at the coroner’s office Wednesday evening. (CBSLA)

She had one plea for the public.

“All I ask is that you don’t forget about him,” Jessica said, “he was a hard-working man and was loved by many. He would want us to continue his legacy and never forget him.”

“This is a moment that I dread,” Villanueva said, “And it happened sooner than I thought.”

He added, “I didn’t know him personally. But in the hallway in front of his ICU room, I could see the tears of each one of his co-workers….and I could feel their loss. That is my loss, the loss of everyone.”

The suspect has been identified 30-year-old Rhett McKenzie Nelson of Saint George, Utah, the sheriff’s department reports.

Nelson is being held on $2 million bail.

It was announced Wednesday that he is also a suspect in the armed robbery of five convenience stores in the San Diego area.

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Solano, off-duty and in civilian clothes, was ordering food shortly before 6 p.m. Monday at a Jack in the Box at 2531 W Valley Blvd. when a man walked up behind him brandishing a handgun and shot him in the back of the head, according to the sheriff’s department.