It's a call no law enforcement agency ever wants to get.
An officer seriously injured, even killed in the line of duty - and the suspect is still out there.
And now in North Carolina there's a new system - a lot like an AMBER alert - but called a blue alert.
It's designed to help officers apprehend that suspect -- and keep the public safe from the threat.
This isn't just because of recent violence against police -- this new law has been in the works since May.
Governor Pat McCrory passed it Monday.
Just like an AMBER alert -- you would get blue alerts on your phone and see the signs on the highway.
A blue alert could go out if:
-a law enforcement officer is killed -- or seriously injured and the suspect is on the loose.
-if an officer can't be found while he's on duty.
-or if a person becomes a serious risk to a law enforcement officer or the public.
-if there's a imminent, credible threat to law enforcement and alert would go out internally to the agency.
Officers say the blue alerts will only help them do their job.
"This person hurt or killed an officer, which means somebody else is going to be in peril also," says Major Jonathan Jacobs with the Guilford County Sheriff's Office. "If we get a tag number, somebody's traveling down the road and sees it they call 911 we can get on it very quickly."
Here's how it works:
The agency contacts State Highway Patrol with the suspect's name and description and car information.
If an officer is missing, the officer's description will be sent out.
"It doesn't happen very often here," Major Jacobs adds. "Thank goodness. But it has happened and having this as an asset is really good for not only us but the general public to assist us and keep them safe.
North Carolina is the 27th state in the county to adopt a blue alert system.
The system should be up and running for local agencies, within the next few weeks.