Updated

A middle-class family of four vanishes, leaving their dogs unattended and rotting food in their San Diego County home.

Their abandoned car is later found near the Mexico border.

It might sound like a TV mystery, but the reality has relatives of the McStay family pleading for help and law enforcement searching both sides of the border for clues.

On Wednesday, the San Diego County Sheriff's Department released photographs of Joseph McStay, 40; his wife Summer, 43; and their sons Gianni, 4, and Joseph Jr., 3.

The family has not been seen or heard from since Feb. 4. Their white, 1996 Isuzu Trooper was found four days later in a strip mall in San Ysidro, about 70 miles from their home in Fallbrook, sheriff's Lt. Dennis Brugos said.

"It's all a mystery," he said. "Is the vehicle down by the border a ploy? Were they voluntarily missing? Were they taken against their will? ... Just for a family of four to disappear, I've never seen anything like it."

Joseph's brother, Michael, went to the home on Feb. 14 to check on the family but only found the dogs. He called authorities the next day, and investigators found no signs of a struggle.

Still, Michael McStay said he fears for the lives of his family members and feels helpless to do anything.

Neighbors said they had been feeding the animals but had heard nothing from the family. Acquaintances told investigators the McStays never would have left on vacation or for any other reason without telling someone.

San Diego County Crime Stoppers is offering a reward of up to $1,000 for information leading to an arrest in the case.

Relatives have set up a Web site seeking information about the family's whereabouts. It's full of pictures of the couple and their children, snacking on ice cream, smiling and posing formally.

"Joseph, Summer, Gianni, and Joseph Mateo McStay are sweet people, loving, fun, genuine," the Web site said. "Summer is an incredible mom. Joey is one of a kind. Anyone that knows Joe has a Joey-ism and (a) story sure to make you smile and laugh. Let's bring them home safe!!!!!"

McStay worked out of his home, designing and installing indoor water fountains. Investigators were checking the family's phone and financial records and have spoken to acquaintances, but so far have found nothing to explain why they vanished or indicate they ran afoul of criminals.

Neighbors didn't recall any major marital disputes.

The Sheriff's Department also is working with authorities in Mexico and has contacted Interpol to ask for help. They also were checking border-crossing surveillance tapes.