Investigators trying to find a 3-year-old kidnap victim, snatched from his home by armed robbers who threatened to kill him, have received dozens of tips but no solid leads, officials said Tuesday.

There was no ransom demand 48 hours after the abduction, and San Bernardino County sheriff's Lt. Rick Ells said detectives were worried that news vans outside the home could be deterring the kidnappers from making contact.

"Every minute, every second that passes, is critical," Sgt. Doug Hubbard said at a news conference. "But we are remaining positive and investigating it as if we just went on scene."

Two gunmen burst through the family's front door Sunday and tied up 3-year-old Briant Rodriguez, four of his siblings and their mother, Maria Rosalina Millan, then ransacked the house, stealing money and other property, the Sheriff's Department said.

After about 20 minutes, the men left with Briant, ordering his mother and the other children not to call police, the department said in a statement.

"They grabbed my kid, told me `I'm going to take the kid to Mexico and I'm going to kill him,"' the distraught Millan said in Spanish to reporters gathered in her front yard Monday night. "I said `Why? Don't take my kid,' and he told me to `turn around, I'm going to shoot you. Stop talking."'

No motive had been established and federal and local investigators were looking at several theories, including that the Spanish-speaking kidnappers were from Mexico and may have had ties to organized crime there.

Authorities along the Mexican border were put on alert and FBI agents were helping in the investigation.

Sheriff's spokeswoman Cindy Beavers said investigators were considering all possibilities but had no substantial leads.

"They've been looking at many, many avenues," she said.

Briant's older brother said the men tried to steal the family car but got mad when they couldn't find the keys.

"They took my little brother. He didn't know what was happening so he wasn't crying," 14-year-old Benjamin Barasa told KNBC-TV.

One of the children — an 8-year-old boy — wiggled free from his ties and freed the rest of the family, authorities said. Briant is the youngest of Millan's seven children. Her 16-year-old son was not home and an adult child does not live at home.

The boy's father was at work at the time and the initial investigation pointed to the kidnappers being strangers to the family, Ells said. The gunmen stole Millan's cell phone, so she had to make the emergency call from a nearby liquor store, Ells said.

The California Highway Patrol didn't issue an Amber Alert for Briant until about nine hours after the family called San Bernardino County authorities. According to the CHP Web site, one requirement for activating an Amber Alert is that information be available that could assist in a child's safe recovery. In this case, however, police said they had no witness descriptions of the abductors' vehicle that could be posted on highway information signs to help locate the suspects.

CHP Officer Daniel Hesser in San Bernardino said the agency received the request for an Amber Alert about 7 1/2 hours after the kidnapping.

The family lives in a modest, single-story home in a mainly lower-income area abutting the city of San Bernardino, about 60 miles east of Los Angeles.