The text message was widely reported across the state in Los Angeles, San Francisco, San Diego, and Sacramento.
The alert was so loud, it caught many people off guard.
Officials even admitted it was a bit scary.
The message was delivered to all devices capable of receiving the alerts in the state of California.
Almost instantly, it became a top trending term worldwide on Twitter.
Officials issued the alert for two children kidnapped in eastern San Diego County after the body of their mother and another child were found in the burning rubble of their home on Sunday.
Police believe James Lee DiMaggio, 40, abducted the kids and is on the run, possibly headed for Texas or Canada. He's believed to be driving a blue Nissan Versa.
DiMaggio may have cut his beard and now look like this.
Anyone with information is asked to call 911 or the San Diego County Sheriff at (858) 565-5200. More information from the CHP can be found here.