SAN BERNARDINO, Calif. Investigators were searching Monday for a 3-year-old boy kidnapped by two gunmen who broke into his family's home, tied up his mother and his four siblings, and stole property, authorities said.

The California Highway Patrol issued an Amber Alert late Sunday for 3-year-old Briant Rodriguez, about nine hours after he was taken from his San Bernardino home.

The men, each carrying a handgun, burst through the front door, tied up the woman and the five children, then ransacked the house and stole money and other property, sheriff's spokeswoman Cindy Beavers said.

Beavers said the boy's father was at work at the time.

The men left with Briant, telling the still-bound mother and the other children not to call police.

One of the children freed himself and untied the rest of the family, Beavers said. She did not know the ages of the rest of the children but said she believed Briant was the youngest.

The mother told investigators she did not know the two men, one estimated to be 18 years old, the other 24.

"We have no idea why they took the child," Beavers said. "They were strangers to the whole family."

No witnesses saw the men's vehicle.

Briant is a Hispanic boy 3 feet tall and weighs 40 pounds, with brown eyes and long, curly brown hair. He was wearing a yellow shirt, blue-striped shorts and black sandals when he was taken.

San Bernardino is about 60 miles east of downtown Los Angeles.