A couple loading groceries into their car at a Chula Vista Costco Wholesale Monday afternoon was ambushed and shot by the mother's estranged lover while their infant son rested feet away in a stroller.

At 12:58 p.m., Chula Vista police rushed to the store located on Broadway and Palomar Street just east of Interstate 5, and next to Walmart, Target and Michael's stores.

Family of the victims told NBC 7 the infant is just six days old. He was not injured in the incident.

"We have had several witnesses that were interviewed that said the victims were putting their groceries away when the suspect approached from behind and began firing at them," said Lt. Dan Peak with the Chula Vista Police Department.

Witnesses say the suspect shot at the mother first, then walked to a nearby produce box where more ammunition was allegedly stored, reloaded, and fired several shots at the father. One witness said the man was trying to protect his girlfriend, placing himself between her and the gunman while he was shot.

NBC 7's Allison Ash reports.

"This other guy was like holding her really tight. I guess he was trying to protect her. He ended up getting shot," witness Angela Shelton said.

Witnessed also say the suspect's gun was muzzled by a water bottle to suppress the sound of the gunfire.

"It was some sort of home made silencer or something. It was just a soft 'pop, pop, pop,' and I thought it was a paint ball or something," a man told NBC 7.

CVPD Lt. Dan Peak explains preliminary details regarding a fatal shooting Monday in the parking lot of Costco.

The gunfire ended when the suspect turned the gun on himself and took his own life.

The victims were rushed into surgery at UCSD Hospital, police said. A CVPD detective told NBC 7 the father is able to communicate despite being shot five times.

The identities of all those involved have been not been released by CVPD. Family members of the victims told NBC 7 the mother is from Chula Vista and said the father, Samuel Valdez, traveled from Oakland to be in town for his son's birth.

A couple loading groceries into their car at a Chula Vista Costco Wholesale Monday afternoon was ambushed and shot by the mother's estranged lover while their infant son rested feet away in a stroller.

One witness told NBC 7 she was two steps away from the victims and said she feared for her life.

"I was walking to my car when I see a guy with a little gun, like homemade, and he starts to shoot the girl so close to her body," she said. "He finished like three shots."

The woman said she saw the shooter reload the weapon.

"He has more bullets in a box and he put more bullets and he went back and he start shooting," she said.

It was the second shooting at a California Costco in recent days. On Friday, an off-duty officer opened fire after Kenneth French, 32, of Riverside, attacked him without provocation as the officer held his young child, according to police in Corona. The officer was the only one who fired shots, striking French and two of his family members, police said.

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