Widow of murdered U.S. Marine reveals her anguish

The widow of a U.S. Marine who was shot and killed in California has spoken of her grief.

"This hurts so much.. I can feel it in my chest my heart aches.. I’m so crushed," Alexia Truax wrote on Facebook.

Her husband, Sgt. Christopher Truax Jr, was found inside a stopped car shortly after midnight on Friday, west of San Diego.

He had suffered a gunshot wound to his head, reports U.S. media.

Sgt Truax's death is being treated as murder and authorities are now hunting his killer.

A woman, who was in the driver's seat of the car, is being treated as a witness and not a suspect.

Investigators have not revealed the woman's identity.

Sgt Truax leaves behind an 11-month-old son.

His wife has described Truax as a "a remarkable man, lover and father".

"His dream was always to become a drill instructor," Alexia told NBC 7.

"My heart hurts so much and it kills me to know I will never be able to hear [his] voice again," she told Fox News.

"I will be praying for [him] each and everyday just how I always have been."

"I look up to the sky and talk to you, what I would give just to hear you talk back," she wrote on Facebook.

"My love your son and I love you way more then you could ever imagine. You will forever be in my mind and in our hearts. Chris Truax I love you Christopher."

The 21-year-old joined the Marine Corps in July 2014 and had been awarded the Navy and Marine Corps Achievement Medal.