Monday marked the first time in California that officials notified the public of a statewide Amber Alert through their cellphones, a California Highway Patrol official said.
It differed from phone to phone, but sometime between late Monday and early Tuesday many mobile phones across Southern California received an Amber Alert related to two missing children in San Diego.
James Lee DiMaggio is suspected of killing Christina Anderson, 44, of Lakeside and kidnapping one or both of her children: Hannah Anderson, 16, and Ethan Anderson, 8.
Christina Anderson's body was found Sunday night in the burning rubble of a house in the rural community of Boulevard in eastern San Diego County, authorities said.
The two children were likely abducted about 5 p.m. on Saturday, authorities said.
Amber Alerts sent out overnight described the vehicle DiMaggio is believed to be traveling in: a blue Nissan Versa with California license plate 6WCU986. Authorities believe he may be making his way north to Canada.
Some cellphones received only a text message, others buzzed and beeped. Some people got more than one alert.
It's all thanks to the Wireless Emergency Alert program, a cellphone version of the Emergency Alert System that gives you the high-pitched test tone on your television.
Cellphone owners receive messages automatically, based on their proximity to the emergency, not based on their phone number.
"If you're from Texas and that's where your phone number is based and you're traveling in California at the time of the Amber Alert, you'll receive the text message about the Amber Alert in California on your Texas-based phone," said CHP spokeswoman Fran Clader.
The messages go out over a special wireless carrier channel called Cell Broadcast and aren't affected by regular cellphone traffic that might disrupt calls and text messages during times of heavy usage, according to the National Center for Missing & Exploited Children, which has teamed with the government in the program.
The signal is transmitted simultaneously to all mobile devices within the range of cell towers in the affected area. There are no texting charges. The system does not track phones' whereabouts.
The system is a second-generation Amber Alert and replaces the Wireless Amber Alert program that sent text alerts only to cellphone users who subscribed to the service. The new system began Jan. 1 and requires cellphone customers to opt out to stop receiving alerts.
Hannah Anderson is described as 5-foot-7, 115 pounds with blond hair, blue eyes, a belly button ring, nose stud and pierced ears.
Ethan Anderson is described as 4-foot-11, 65 pounds with sandy blond hair.
DiMaggio is described as 5-foot-9, 150 pounds with brown hair and brown eyes.
Anyone with information on the case is asked to call the homicide detail at (858) 974-2321 or (858) 565-5200, or San Diego County Crime Stoppers at (888) 580-8477.
The Amber Alert program was created in 1996 in honor of 9-year-old Amber Hagerman, who was abducted and murdered near her home in Arlington, Texas.