Updated

An Orange County man who was hunted statewide after shooting his estranged wife and kidnapping their 9-year-old son may be in Mexico, authorities said Saturday after his rented motor home was found abandoned in a tiny border town.

The Imperial County Sheriff's Department notified Orange County investigators Saturday morning that a 39-foot purple-and-gold motor home rented by Lonnie Ramos was found in the community of Andrade, said Orange County sheriff's Lt. Ted Boyne.

"It's a breakthrough," Boyne said. "We have the vehicle. There's a point from which to work."

A witness told authorities they saw the two cross into Mexico on foot two days ago, Boyne said. It was not immediately clear why the witness waited so long to contact Imperial County authorities.

Andrade is on the border, about 5 miles west of Yuma, Ariz., and about 160 miles east of San Diego. Investigators earlier had notified Mexican authorities that Ramos might be heading that way.

Boyne said they were sending sheriff's investigators down to the area.

Ramos, 46, shot his estranged wife in the face on Wednesday as she went to his home in the southern county community of Portola Hills to pick up their son, Ryan, after a custody visit, authorities contend.

Gynnae Ramos, 41, was critically wounded but expected to survive.

After the shooting, a statewide Amber Alert was issued for two cars that Ramos might have been driving. The motor home was added after someone reported renting it to the fugitive.

Ramos apparently tried to buy plane tickets for himself and his son at John Wayne airport Wednesday night but was unable to do so because he refused to show any identification or provide his name, Orange County sheriff's spokesman Jim Amormino said.

Ramos' wife filed for divorce in 2003 and the two have been locked in a bitter divorce and custody battle, court records indicated.